diff --git a/thu_learn_downloader/client/course.py b/thu_learn_downloader/client/course.py
index d9c2d78..fef5bbe 100644
--- a/thu_learn_downloader/client/course.py
+++ b/thu_learn_downloader/client/course.py
@@ -42,6 +42,7 @@
                 params={"wlkcid": self.id, "size": MAX_SIZE},
             ).json()["object"]
         ]
+        documents.sort(key=lambda document: document.title)
         documents.sort(key=lambda document: document.upload_time)
         return documents