diff --git a/app/port/controller/PackageVersionFileController.ts b/app/port/controller/PackageVersionFileController.ts
index af277525..60316bab 100644
--- a/app/port/controller/PackageVersionFileController.ts
+++ b/app/port/controller/PackageVersionFileController.ts
@@ -145,10 +145,20 @@ export class PackageVersionFileController extends AbstractController {
     }
 
     const file = await this.packageVersionFileService.showPackageVersionFile(packageVersion, path);
+    const hasMeta = typeof meta === 'string';
+
     if (!file) {
+      const possibleFile = await this.#searchPossibleEntries(packageVersion, path);
+
+      if (possibleFile) {
+        const route = `/${fullname}/${versionSpec}/files${possibleFile.path}${hasMeta ? '?meta' : ''}`;
+        ctx.redirect(route);
+        return;
+      }
+
       throw new NotFoundError(`File ${fullname}@${versionSpec}${path} not found`);
     }
-    const hasMeta = typeof meta === 'string';
+
     if (hasMeta) {
       ctx.set('cache-control', META_CACHE_CONTROL);
       return formatFileItem(file);
@@ -161,6 +171,28 @@ export class PackageVersionFileController extends AbstractController {
     return await this.distRepository.getDistStream(file.dist);
   }
 
+  /**
+   * compatibility with unpkg
+   * 1. try to match alias entry. e.g. accessing `index.js` or `index.json` using /index
+   * 2. if given path is directory and has `index.js` file, redirect to it. e.g. using `lib` alias to access `lib/index.js`
+   * @param packageVersion
+   * @param path
+   * @return
+   */
+  async #searchPossibleEntries(packageVersion: any, path: string) {
+    const possiblePath = [ `${path}.js`, `${path}.json`, `${path}/index.js` ];
+
+    const possibleFiles = possiblePath.map(pathItem => this.packageVersionFileService.showPackageVersionFile(packageVersion, pathItem));
+
+    const files = await Promise.allSettled(possibleFiles);
+
+    for (const file of files) {
+      if (file.status === 'fulfilled' && file.value) {
+        return file.value;
+      }
+    }
+  }
+
   async #getPackageVersion(ctx: EggContext, fullname: string, scope: string, name: string, versionSpec: string) {
     const { blockReason, packageVersion } = await this.packageManagerService.showPackageVersionByVersionOrTag(
       scope, name, versionSpec);