diff --git a/codes/cpp/chapter_hashing/hash_map_chaining.cpp b/codes/cpp/chapter_hashing/hash_map_chaining.cpp
index 17ca744cc..ef8fc11d5 100644
--- a/codes/cpp/chapter_hashing/hash_map_chaining.cpp
+++ b/codes/cpp/chapter_hashing/hash_map_chaining.cpp
@@ -92,6 +92,8 @@ class HashMapChaining {
         for (auto &bucket : bucketsTmp) {
             for (Pair *pair : bucket) {
                 put(pair->key, pair->val);
+                // 释放内存
+                delete pair;
             }
         }
     }