diff --git a/packages/core/src/utils/syntax.ts b/packages/core/src/utils/syntax.ts
index 108f51426..a62c93612 100644
--- a/packages/core/src/utils/syntax.ts
+++ b/packages/core/src/utils/syntax.ts
@@ -173,7 +173,10 @@ export function transformSyntaxToRspackTarget(
         ) {
           return 'es2022';
         }
-
+        // The es6 is the same as es2015, compatible with rspack API schema
+        if (normalizedSyntaxItem === 'es6') {
+          return 'es2015';
+        }
         return normalizedSyntaxItem;
       }
 
diff --git a/packages/core/tests/syntax.test.ts b/packages/core/tests/syntax.test.ts
index 272595b70..58269e122 100644
--- a/packages/core/tests/syntax.test.ts
+++ b/packages/core/tests/syntax.test.ts
@@ -153,6 +153,7 @@ describe('transformSyntaxToBrowserslist', () => {
 
 describe('transformSyntaxToRspackTarget', () => {
   test('esX', () => {
+    const es6 = transformSyntaxToRspackTarget('es6');
     const es2023 = transformSyntaxToRspackTarget('es2023');
     const es2024 = transformSyntaxToRspackTarget('es2024');
     const esnext = transformSyntaxToRspackTarget('esnext');
@@ -160,6 +161,12 @@ describe('transformSyntaxToRspackTarget', () => {
     expect(es2023).toEqual(es2024);
     expect(es2023).toEqual(esnext);
 
+    expect(es6).toMatchInlineSnapshot(`
+      [
+        "es2015",
+      ]
+    `);
+
     expect(es2023).toMatchInlineSnapshot(
       `
       [
@@ -186,5 +193,14 @@ describe('transformSyntaxToRspackTarget', () => {
         "es2022",
       ]
     `);
+
+    expect(
+      transformSyntaxToRspackTarget(['Chrome 123', 'es6']),
+    ).toMatchInlineSnapshot(`
+      [
+        "browserslist:Chrome 123",
+        "es2015",
+      ]
+    `);
   });
 });