diff --git a/contracts/WTFSBT1155Minter.sol b/contracts/WTFSBT1155Minter.sol
index 4b5f5ce..9c82d3a 100644
--- a/contracts/WTFSBT1155Minter.sol
+++ b/contracts/WTFSBT1155Minter.sol
@@ -12,9 +12,18 @@ contract WTFSBT1155Minter is Ownable, Nonces {
     using ECDSA for bytes32;
 
     /* ============ Events ============ */
-    /// @notice This event is emitted when signer address is changed
+    /**
+     * @dev This event is emitted when the signer address is changed
+     * @param oldSigner The address of the old signer
+     * @param newSigner The address of the new signer
+     */
     event SignerChanged(address indexed oldSigner, address indexed newSigner);
-    /// @notice This event is emitted when new SBT is minted
+    /**
+     * @dev This event is emitted when a new SBT is minted
+     * @param to The address to which the SBT is minted
+     * @param soulId The ID of the SBT
+     * @param donation The donation amount sent during the mint
+     */
     event SBTMinted(
         address indexed to,
         uint256 indexed soulId,
@@ -22,12 +31,16 @@ contract WTFSBT1155Minter is Ownable, Nonces {
     );
 
     /* ============ State Variables ============ */
-    address public signer; // singer address
+    address public signer; // Signer address
     WTFSBT1155 public wtfsbt; // WTF SBT ERC1155 contract address
-    uint256 public immutable _cachedChainId;
+    uint256 public immutable _cachedChainId; // Cached chain ID for replay protection
 
     /* ============ Constructor ============ */
-    /// @notice initialize WTFSBT1155 addresss and signer address
+    /**
+     * @dev Initializes the WTFSBT1155 contract address and signer address
+     * @param sbtAddr_ The address of the WTFSBT1155 contract
+     * @param signer_ The address of the initial signer
+     */
     constructor(address payable sbtAddr_, address signer_) Ownable(msg.sender) {
         wtfsbt = WTFSBT1155(sbtAddr_);
         signer = signer_;
@@ -35,7 +48,17 @@ contract WTFSBT1155Minter is Ownable, Nonces {
     }
 
     /* ============ Public Functions ============ */
-    // @dev verify whether a signature is valid
+    /**
+     * @dev Verifies whether a signature is valid
+     * @param to The address to which the SBT will be minted
+     * @param soulId The ID of the SBT
+     * @param mintPrice The price of minting the SBT
+     * @param deadline The deadline until which the signature is valid
+     * @param chainId The chain ID for replay protection
+     * @param nonces The nonce to prevent replay attacks
+     * @param signature The signature to verify
+     * @return True if the signature is valid, false otherwise
+     */
     function verifySignature(
         address to,
         uint256 soulId,
@@ -45,25 +68,24 @@ contract WTFSBT1155Minter is Ownable, Nonces {
         uint256 nonces,
         bytes memory signature
     ) public view returns (bool) {
-        // 生成用于签名的消息
+        // Generate the message for signature
         bytes32 message = keccak256(
             abi.encodePacked(to, soulId, mintPrice, deadline, chainId, nonces)
         );
         bytes32 ethSignedMessage = message.toEthSignedMessageHash();
 
-        // 恢复签名者地址
+        // Recover the address of the signer
         return signer == ethSignedMessage.recover(signature);
     }
 
     /* ============ External Functions ============ */
     /**
-     * @dev mint token `soulId` to `account` if `signature` is valid.
-     * `msgHash` is concatenated by `soulId` and `account`.
-     * @param to: mint address
-     * @param soulId: ERC1155 token id
-     * @param mintPrice: token mint price
-     * @param deadline: token mint deadline
-     * @param signature: signature by signer
+     * @dev Mints a token `soulId` to `to` if the `signature` is valid
+     * @param to The address to which the SBT will be minted
+     * @param soulId The ID of the SBT
+     * @param mintPrice The price of minting the SBT
+     * @param deadline The deadline until which the signature is valid
+     * @param signature The signature to verify
      */
     function mint(
         address to,
@@ -99,24 +121,26 @@ contract WTFSBT1155Minter is Ownable, Nonces {
     }
 
     /**
-     * @dev recover sbt to new address. only owner can call.
-     * @param oldOwner The old owner address for SBT.
-     * @param newOwner The new owner address for SBT.
+     * @dev Recovers SBTs to a new address. Only the owner can call this function.
+     * @param oldOwner The old owner address for SBT
+     * @param newOwner The new owner address for SBT
      */
     function recover(address oldOwner, address newOwner) external onlyOwner {
         wtfsbt.recover(oldOwner, newOwner);
     }
 
     /**
-     * @dev change signer address. only owner can call.
-     * @param newSigner: address of new signer
+     * @dev Changes the signer address. Only the owner can call this function.
+     * @param newSigner The address of the new signer
      */
     function setSigner(address newSigner) external onlyOwner {
         signer = newSigner;
         emit SignerChanged(signer, newSigner);
     }
 
-    // withdraw eth
+    /**
+     * @dev Withdraws the contract's balance. Only the owner can call this function.
+     */
     function withdraw() external onlyOwner {
         payable(owner()).transfer(address(this).balance);
     }