diff --git a/docs/config/engineer.md b/docs/config/engineer.md
index 326d63878..b8664f763 100644
--- a/docs/config/engineer.md
+++ b/docs/config/engineer.md
@@ -173,7 +173,7 @@ export interface GenerateAIPromptType {
   type: string
   defaultScope?: string
   maxSubjectLength?: number
-  upperCaseSubject?: boolean
+  upperCaseSubject?: boolean | null
   diff?: string
 }
 ```
@@ -188,8 +188,11 @@ module.exports = {
 ## upperCaseSubject
 
 - **description** : Whether to automatically capitalize the first character of the short description (subject)
-- **type** : `boolean`
-- **default** : `false`
+- **type** : `boolean` | `null`
+    - `null`: Do not process
+    - `true`: Automatically capitalize the first letter
+    - `false`: Automatically lowercase the first letter
+- **default** : `null`
 
 ## breaklineNumber
 
diff --git a/docs/public/schema/cz-git.json b/docs/public/schema/cz-git.json
index 24d047652..30976e03e 100644
--- a/docs/public/schema/cz-git.json
+++ b/docs/public/schema/cz-git.json
@@ -180,9 +180,12 @@
           "default": "empty"
         },
         "upperCaseSubject": {
-          "type": "boolean",
-          "description": "Subject is need upper case first.",
-          "default": false
+          "type": [
+            "boolean",
+            "null"
+          ],
+          "description": "Subject is need upper case first.\n\n- `null`: Do not enforce capitalization of the first letter\n- `true`: Enforce capitalization of the first letter\n- `false`: Enforce lowercase for the first letter",
+          "default": null
         },
         "markBreakingChangeMode": {
           "type": "boolean",
diff --git a/docs/snippets/.commitlintrc b/docs/snippets/.commitlintrc
index 923a32798..ad810b386 100644
--- a/docs/snippets/.commitlintrc
+++ b/docs/snippets/.commitlintrc
@@ -42,7 +42,7 @@
     "customScopesAlign": "bottom",
     "customScopesAlias": "custom",
     "emptyScopesAlias": "empty",
-    "upperCaseSubject": false,
+    "upperCaseSubject": null,
     "markBreakingChangeMode": false,
     "allowBreakingChanges": ["feat", "fix"],
     "breaklineNumber": 100,
diff --git a/docs/snippets/.czrc b/docs/snippets/.czrc
index 59f16fc8c..a026b4e34 100644
--- a/docs/snippets/.czrc
+++ b/docs/snippets/.czrc
@@ -39,7 +39,7 @@
   "customScopesAlign": "bottom",
   "customScopesAlias": "custom",
   "emptyScopesAlias": "empty",
-  "upperCaseSubject": false,
+  "upperCaseSubject": null,
   "markBreakingChangeMode": false,
   "allowBreakingChanges": ["feat", "fix"],
   "breaklineNumber": 100,
diff --git a/docs/snippets/commitlint.config.cjs b/docs/snippets/commitlint.config.cjs
index 8566e2ea9..dd0bbbf5c 100644
--- a/docs/snippets/commitlint.config.cjs
+++ b/docs/snippets/commitlint.config.cjs
@@ -44,7 +44,7 @@ module.exports = defineConfig({
         customScopesAlign: 'bottom',
         customScopesAlias: 'custom',
         emptyScopesAlias: 'empty',
-        upperCaseSubject: false,
+        upperCaseSubject: null,
         markBreakingChangeMode: false,
         allowBreakingChanges: ['feat', 'fix'],
         breaklineNumber: 100,
diff --git a/docs/snippets/commitlint.config.cn-en.js b/docs/snippets/commitlint.config.cn-en.js
index ba954026c..2a9870c31 100644
--- a/docs/snippets/commitlint.config.cn-en.js
+++ b/docs/snippets/commitlint.config.cn-en.js
@@ -42,7 +42,7 @@ module.exports = defineConfig({
         customScopesAlign: 'bottom',
         customScopesAlias: 'custom',
         emptyScopesAlias: 'empty',
-        upperCaseSubject: false,
+        upperCaseSubject: null,
         markBreakingChangeMode: false,
         allowBreakingChanges: ['feat', 'fix'],
         breaklineNumber: 100,
diff --git a/docs/snippets/commitlint.config.cn.js b/docs/snippets/commitlint.config.cn.js
index c3e37b1b4..8b0f236d8 100644
--- a/docs/snippets/commitlint.config.cn.js
+++ b/docs/snippets/commitlint.config.cn.js
@@ -44,7 +44,7 @@ module.exports = defineConfig({
         customScopesAlign: 'bottom',
         customScopesAlias: '以上都不是？我要自定义',
         emptyScopesAlias: '跳过',
-        upperCaseSubject: false,
+        upperCaseSubject: null,
         markBreakingChangeMode: false,
         allowBreakingChanges: ['feat', 'fix'],
         breaklineNumber: 100,
diff --git a/docs/snippets/commitlint.config.emoji.js b/docs/snippets/commitlint.config.emoji.js
index 7f6b4c83d..d019c2448 100644
--- a/docs/snippets/commitlint.config.emoji.js
+++ b/docs/snippets/commitlint.config.emoji.js
@@ -44,7 +44,7 @@ module.exports = defineConfig({
         customScopesAlign: 'bottom',
         customScopesAlias: 'custom',
         emptyScopesAlias: 'empty',
-        upperCaseSubject: false,
+        upperCaseSubject: null,
         markBreakingChangeMode: false,
         allowBreakingChanges: ['feat', 'fix'],
         breaklineNumber: 100,
diff --git a/docs/snippets/commitlint.config.mjs b/docs/snippets/commitlint.config.mjs
index 4fbd4581c..c36ff7b5f 100644
--- a/docs/snippets/commitlint.config.mjs
+++ b/docs/snippets/commitlint.config.mjs
@@ -44,7 +44,7 @@ export default defineConfig({
         customScopesAlign: 'bottom',
         customScopesAlias: 'custom',
         emptyScopesAlias: 'empty',
-        upperCaseSubject: false,
+        upperCaseSubject: null,
         markBreakingChangeMode: false,
         allowBreakingChanges: ['feat', 'fix'],
         breaklineNumber: 100,
diff --git a/docs/snippets/commitlint.config.without-fn.cjs b/docs/snippets/commitlint.config.without-fn.cjs
index 46c32a568..cac5fc771 100644
--- a/docs/snippets/commitlint.config.without-fn.cjs
+++ b/docs/snippets/commitlint.config.without-fn.cjs
@@ -43,7 +43,7 @@ module.exports = {
         customScopesAlign: 'bottom',
         customScopesAlias: 'custom',
         emptyScopesAlias: 'empty',
-        upperCaseSubject: false,
+        upperCaseSubject: null,
         markBreakingChangeMode: false,
         allowBreakingChanges: ['feat', 'fix'],
         breaklineNumber: 100,
diff --git a/docs/snippets/commitlint.config.without-fn.mjs b/docs/snippets/commitlint.config.without-fn.mjs
index 9c517c244..f039cec93 100644
--- a/docs/snippets/commitlint.config.without-fn.mjs
+++ b/docs/snippets/commitlint.config.without-fn.mjs
@@ -43,7 +43,7 @@ export default {
         customScopesAlign: 'bottom',
         customScopesAlias: 'custom',
         emptyScopesAlias: 'empty',
-        upperCaseSubject: false,
+        upperCaseSubject: null,
         markBreakingChangeMode: false,
         allowBreakingChanges: ['feat', 'fix'],
         breaklineNumber: 100,
diff --git a/docs/snippets/cz.config.cjs b/docs/snippets/cz.config.cjs
index ec64ef037..00923559b 100644
--- a/docs/snippets/cz.config.cjs
+++ b/docs/snippets/cz.config.cjs
@@ -40,7 +40,7 @@ module.exports = definePrompt({
     customScopesAlign: 'bottom',
     customScopesAlias: 'custom',
     emptyScopesAlias: 'empty',
-    upperCaseSubject: false,
+    upperCaseSubject: null,
     markBreakingChangeMode: false,
     allowBreakingChanges: ['feat', 'fix'],
     breaklineNumber: 100,
diff --git a/docs/snippets/cz.config.mjs b/docs/snippets/cz.config.mjs
index 6fe0ecc3d..d7b913ebe 100644
--- a/docs/snippets/cz.config.mjs
+++ b/docs/snippets/cz.config.mjs
@@ -40,7 +40,7 @@ export default definePrompt({
     customScopesAlign: 'bottom',
     customScopesAlias: 'custom',
     emptyScopesAlias: 'empty',
-    upperCaseSubject: false,
+    upperCaseSubject: null,
     markBreakingChangeMode: false,
     allowBreakingChanges: ['feat', 'fix'],
     breaklineNumber: 100,
diff --git a/docs/snippets/cz.config.without-fn.cjs b/docs/snippets/cz.config.without-fn.cjs
index 859ee0700..fbb92ed95 100644
--- a/docs/snippets/cz.config.without-fn.cjs
+++ b/docs/snippets/cz.config.without-fn.cjs
@@ -39,7 +39,7 @@ module.exports = {
     customScopesAlign: 'bottom',
     customScopesAlias: 'custom',
     emptyScopesAlias: 'empty',
-    upperCaseSubject: false,
+    upperCaseSubject: null,
     markBreakingChangeMode: false,
     allowBreakingChanges: ['feat', 'fix'],
     breaklineNumber: 100,
diff --git a/docs/snippets/cz.config.without-fn.mjs b/docs/snippets/cz.config.without-fn.mjs
index ea6249174..3517af702 100644
--- a/docs/snippets/cz.config.without-fn.mjs
+++ b/docs/snippets/cz.config.without-fn.mjs
@@ -39,7 +39,7 @@ export default {
     customScopesAlign: 'bottom',
     customScopesAlias: 'custom',
     emptyScopesAlias: 'empty',
-    upperCaseSubject: false,
+    upperCaseSubject: null,
     markBreakingChangeMode: false,
     allowBreakingChanges: ['feat', 'fix'],
     breaklineNumber: 100,
diff --git a/docs/zh/config/engineer.md b/docs/zh/config/engineer.md
index 281fc8941..2c2cd1cd2 100644
--- a/docs/zh/config/engineer.md
+++ b/docs/zh/config/engineer.md
@@ -178,7 +178,7 @@ export interface GenerateAIPromptType {
   type: string
   defaultScope?: string
   maxSubjectLength?: number
-  upperCaseSubject?: boolean
+  upperCaseSubject?: boolean | null
   diff?: string
 }
 ```
@@ -209,8 +209,11 @@ module.exports = {
 ## upperCaseSubject
 
 - **描述** : 是否自动将 <ruby>简短描述<rt>subject</rt></ruby> 第一个字符进行大写处理
-- **类型** : `boolean`
-- **默认** : `false`
+- **类型** : `boolean` | `null`
+    - `null`: 不进行处理
+    - `true`: 首字母自动大写
+    - `false`: 首字母自动小写
+- **默认** : `null`
 
 ## breaklineNumber
 
diff --git a/packages/cz-git/src/generator/api.ts b/packages/cz-git/src/generator/api.ts
index bbb575187..d13e4cbb3 100644
--- a/packages/cz-git/src/generator/api.ts
+++ b/packages/cz-git/src/generator/api.ts
@@ -2,7 +2,7 @@ import url from 'node:url'
 import process from 'node:process'
 import { style } from '@cz-git/inquirer'
 import HttpsProxyAgent from 'https-proxy-agent'
-import { isNodeVersionInRange, log } from '../shared'
+import { isNodeVersionInRange, log, transformSubjectCase } from '../shared'
 import type { CommitizenGitOptions } from '../shared'
 
 export async function fetchOpenAIMessage(options: CommitizenGitOptions, prompt: string) {
@@ -88,20 +88,14 @@ function useModelStrategy(options: CommitizenGitOptions, prompt: string) {
 function parseAISubject(options: CommitizenGitOptions, subject?: string) {
     if (!subject)
         return ''
-
-    subject = subject
-        .trim()
-        .replace(/(\r\n|\n|\r)/g, '')
-        .replace(/[.。]$/, '')
-        .replace(/^"|"$/g, '')
-    let res = subject
-    if (options.upperCaseSubject)
-        res = res.charAt(0).toUpperCase()
-    else
-        res = res.charAt(0).toLowerCase()
-    res = res + subject.slice(1)
-
-    return res
+    return transformSubjectCase(
+        options,
+        subject
+            .trim()
+            .replace(/(\r\n|\n|\r)/g, '')
+            .replace(/[.。]$/, '')
+            .replace(/^"|"$/g, ''),
+    )
 }
 
 class APIError extends Error {
diff --git a/packages/cz-git/src/generator/question.ts b/packages/cz-git/src/generator/question.ts
index 1f0d3425e..875cc88cb 100644
--- a/packages/cz-git/src/generator/question.ts
+++ b/packages/cz-git/src/generator/question.ts
@@ -19,6 +19,7 @@ import {
     parseStandardScopes,
     resolveListItemPinTop,
     resovleCustomListTemplate,
+    transformSubjectCase,
     useThemeCode,
 } from '../shared'
 
@@ -174,37 +175,28 @@ export function generateQuestions(options: CommitizenGitOptions, cz: any) {
                     tooltip = `${maxSubjectLength - subjectLength} more chars allowed`
                 }
 
-                tooltip
-          = (
-                        minSubjectLength !== undefined
-                        && subjectLength >= minSubjectLength
-                        && subjectLength <= maxSubjectLength
-                    )
-                        ? style.gray(`[${tooltip}]`)
-                        : isWarning
-                            ? style.yellow(`[${tooltip}]`)
-                            : style.red(`[${tooltip}]`)
-                subject
-          = (
-                        minSubjectLength !== undefined
-                        && subjectLength >= minSubjectLength
-                        && subjectLength <= maxSubjectLength
-                    )
+                tooltip = (
+                    minSubjectLength !== undefined
+                    && subjectLength >= minSubjectLength
+                    && subjectLength <= maxSubjectLength
+                )
+                    ? style.gray(`[${tooltip}]`)
+                    : isWarning
+                        ? style.yellow(`[${tooltip}]`)
+                        : style.red(`[${tooltip}]`)
+                subject = (
+                    minSubjectLength !== undefined
+                    && subjectLength >= minSubjectLength
+                    && subjectLength <= maxSubjectLength
+                )
+                    ? useThemeCode(subject, options.themeColorCode)
+                    : isWarning
                         ? useThemeCode(subject, options.themeColorCode)
-                        : isWarning
-                            ? useThemeCode(subject, options.themeColorCode)
-                            : style.red(subject)
+                        : style.red(subject)
 
                 return `${tooltip}\n` + ` ${subject}`
             },
-            filter: (subject: string) => {
-                const upperCaseSubject = options.upperCaseSubject || false
-
-                return (
-                    (upperCaseSubject ? subject.charAt(0).toUpperCase() : subject.charAt(0).toLowerCase())
-                    + subject.slice(1)
-                )
-            },
+            filter: (subject: string) => transformSubjectCase(options, subject),
         },
         {
             type: 'complete-input',
diff --git a/packages/cz-git/src/shared/types/options.ts b/packages/cz-git/src/shared/types/options.ts
index d793edc69..ea368ee99 100644
--- a/packages/cz-git/src/shared/types/options.ts
+++ b/packages/cz-git/src/shared/types/options.ts
@@ -171,7 +171,7 @@ export interface GenerateAIPromptType {
     type?: string
     defaultScope?: string | string[]
     maxSubjectLength?: number
-    upperCaseSubject?: boolean
+    upperCaseSubject?: boolean | null
     diff?: string
 }
 
@@ -390,9 +390,12 @@ export interface CommitizenGitOptions {
     /**
      * Subject is need upper case first.
      *
-     * @default false
+     * - `null`: Do not process
+     * - `true`: Automatically capitalize the first letter
+     * - `false`: Automatically lowercase the first letter
+     * @default null
      */
-    upperCaseSubject?: boolean
+    upperCaseSubject?: boolean | null
 
     /**
      * Whether to add extra prompt BREAKCHANGE ask. to add an extra "!" to the header
@@ -653,7 +656,7 @@ export const defaultConfig = Object.freeze({
     customScopesAlign: 'bottom',
     customScopesAlias: 'custom',
     emptyScopesAlias: 'empty',
-    upperCaseSubject: false,
+    upperCaseSubject: null,
     markBreakingChangeMode: false,
     allowBreakingChanges: ['feat', 'fix'],
     breaklineNumber: 100,
diff --git a/packages/cz-git/src/shared/utils/util.ts b/packages/cz-git/src/shared/utils/util.ts
index 4ea4ecc6c..ed44144e7 100644
--- a/packages/cz-git/src/shared/utils/util.ts
+++ b/packages/cz-git/src/shared/utils/util.ts
@@ -86,6 +86,7 @@ export function parseStandardScopes(scopes: ScopesType): Option[] {
                     : { value: scope.value, name: scope.name }
     })
 }
+
 /**
  * To get a list of scopes
  *
@@ -197,6 +198,18 @@ export function getProcessSubject(text: string) {
     return text.replace(/(^\s+|[\s.]+$)/g, '') ?? ''
 }
 
+export function transformSubjectCase(options: CommitizenGitOptions, subject: string) {
+    if (!subject || options.upperCaseSubject === null)
+        return subject
+
+    const firstChar = subject[0]
+    const rest = subject.slice(1)
+
+    return options.upperCaseSubject
+        ? firstChar.toUpperCase() + rest
+        : firstChar.toLowerCase() + rest
+}
+
 function getEmojiStrLength(options: CommitizenGitOptions, type?: string): number {
     const item = options.types?.find((i: { value?: string }) => i.value === type)
     // 1: space
diff --git a/scripts/czrc-schema.d.ts b/scripts/czrc-schema.d.ts
index 5efd038cd..6f63956dd 100644
--- a/scripts/czrc-schema.d.ts
+++ b/scripts/czrc-schema.d.ts
@@ -182,9 +182,12 @@ export interface CommitizenGitOptions {
     /**
      * Subject is need upper case first.
      *
-     * @default false
+     * - `null`: Do not process
+     * - `true`: Automatically capitalize the first letter
+     * - `false`: Automatically lowercase the first letter
+     * @default null
      */
-    upperCaseSubject?: boolean
+    upperCaseSubject?: boolean | null
 
     /**
      * Whether to add extra prompt BREAKCHANGE ask. to add an extra "!" to the header