diff --git a/apps/ai-game-creator-shell/src-tauri/src/environment_check.rs b/apps/ai-game-creator-shell/src-tauri/src/environment_check.rs
index 72d2284ed..fbe50c395 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/environment_check.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/environment_check.rs
@@ -1294,6 +1294,28 @@ mod tests {
         assert_eq!(default.version, (22, 23, 3));
     }
 
+    #[cfg(unix)]
+    #[test]
+    fn fnm_default_alias_symlink_selects_the_linked_installation() {
+        use std::os::unix::fs::symlink;
+
+        let fnm_root = tempfile::tempdir().unwrap();
+        let older = install_fnm_version(fnm_root.path(), "v20.11.0");
+        install_fnm_version(fnm_root.path(), "v22.23.3");
+        let alias_dir = fnm_root.path().join("aliases");
+        fs::create_dir_all(&alias_dir).unwrap();
+        // fnm 1.39 的 default 别名是指向安装目录的符号链接，不是版本字符串文件。
+        symlink(&older, alias_dir.join("default")).unwrap();
+        let installed = installed_node_versions(&[fnm_root.path().to_path_buf()], &[]);
+        assert_eq!(installed.len(), 2);
+        let default =
+            default_managed_installation(&installed, &[fnm_root.path().to_path_buf()], &[])
+                .expect("fnm default alias should resolve");
+        // 必须跟随别名选中 v20，而不是回退到最高的 v22。
+        assert_eq!(default.prefix, older.canonicalize().unwrap());
+        assert_eq!(default.version, (20, 11, 0));
+    }
+
     #[test]
     fn version_file_pin_is_authoritative_and_blocks_when_not_installed() {
         let fnm_root = tempfile::tempdir().unwrap();