diff --git a/packages/plugin-legacy/src/index.ts b/packages/plugin-legacy/src/index.ts
index d356793b231c72..6a86372ba30d73 100644
--- a/packages/plugin-legacy/src/index.ts
+++ b/packages/plugin-legacy/src/index.ts
@@ -532,11 +532,13 @@ function viteLegacyPlugin(options: Options = {}): Plugin[] {
       // entirely.
       opts.__vite_force_terser__ = true
 
-      // @ts-expect-error In the `generateBundle` hook,
-      // we'll delete the assets from the legacy bundle to avoid emitting duplicate assets.
-      // But that's still a waste of computing resource.
-      // So we add this flag to avoid emitting the asset in the first place whenever possible.
-      opts.__vite_skip_asset_emit__ = true
+      if (genModern) {
+        // @ts-expect-error In the `generateBundle` hook,
+        // we'll delete the assets from the legacy bundle to avoid emitting duplicate assets.
+        // But that's still a waste of computing resource.
+        // So we add this flag to avoid emitting the asset in the first place whenever possible.
+        opts.__vite_skip_asset_emit__ = true
+      }
 
       // avoid emitting assets for legacy bundle
       const needPolyfills =