diff --git a/scripts/build_sandbox.js b/scripts/build_sandbox.js
index 55e8a79bbc..69b06cb351 100644
--- a/scripts/build_sandbox.js
+++ b/scripts/build_sandbox.js
@@ -135,7 +135,7 @@ function buildImage(imageName, dockerfile) {
   ).version;
 
   const imageTag =
-    process.env.QWEN_SANDBOX_IMAGE_TAG || imageName.split(':')[1];
+    process.env.QWEN_SANDBOX_IMAGE_TAG || imageName.split(':')[1] || 'latest';
   const finalImageName = `${imageName.split(':')[0]}:${imageTag}`;
 
   try {