diff --git a/_internal/package.json b/_internal/package.json
index 084a9ae3c..7dfddcdfd 100644
--- a/_internal/package.json
+++ b/_internal/package.json
@@ -6,7 +6,7 @@
   "private": true,
   "scripts": {
     "watch": "bunchee index.ts -w",
-    "build": "bunchee index.ts --target es2015",
+    "build": "bunchee index.ts",
     "types:check": "tsc --noEmit",
     "clean": "rimraf dist"
   },
diff --git a/core/package.json b/core/package.json
index 27fc5c61e..09b191850 100644
--- a/core/package.json
+++ b/core/package.json
@@ -6,7 +6,7 @@
   "private": true,
   "scripts": {
     "watch": "bunchee index.ts -w",
-    "build": "bunchee index.ts --target es2015",
+    "build": "bunchee index.ts",
     "types:check": "tsc --noEmit",
     "clean": "rimraf dist"
   },