diff --git a/ding/data/buffer/deque_buffer.py b/ding/data/buffer/deque_buffer.py
index 26c7cebc8e..6c4af9cac5 100644
--- a/ding/data/buffer/deque_buffer.py
+++ b/ding/data/buffer/deque_buffer.py
@@ -239,10 +239,17 @@ def count(self) -> int:
     def get(self, idx: int) -> BufferedData:
         """
         Overview:
-            The method that returns the BufferedData object given a specific index.
+            The method that returns the BufferedData object by subscript idx (int).
         """
         return self.storage[idx]
 
+    def get_by_index(self, index: str) -> BufferedData:
+        """
+        Overview:
+            The method that returns the BufferedData object given a specific index (str).
+        """
+        return self.storage[self.indices.get(index)]
+
     @apply_middleware("clear")
     def clear(self) -> None:
         """
diff --git a/ding/data/buffer/middleware/priority.py b/ding/data/buffer/middleware/priority.py
index 017b302a5f..b890bac78f 100644
--- a/ding/data/buffer/middleware/priority.py
+++ b/ding/data/buffer/middleware/priority.py
@@ -108,12 +108,12 @@ def update(self, chain: Callable, index: str, data: Any, meta: Any, *args, **kwa
             self.max_priority = max(self.max_priority, new_priority)
 
     def delete(self, chain: Callable, index: str, *args, **kwargs) -> None:
-        for item in self.buffer.storage:
-            meta = item.meta
-            priority_idx = meta['priority_idx']
-            self.sum_tree[priority_idx] = self.sum_tree.neutral_element
-            self.min_tree[priority_idx] = self.min_tree.neutral_element
-            self.buffer_idx.pop(priority_idx)
+        item = self.buffer.get_by_index(index)
+        meta = item.meta
+        priority_idx = meta['priority_idx']
+        self.sum_tree[priority_idx] = self.sum_tree.neutral_element
+        self.min_tree[priority_idx] = self.min_tree.neutral_element
+        self.buffer_idx.pop(priority_idx)
         return chain(index, *args, **kwargs)
 
     def clear(self, chain: Callable) -> None:
diff --git a/ding/data/buffer/tests/test_middleware.py b/ding/data/buffer/tests/test_middleware.py
index cc19866ee3..94c51ba740 100644
--- a/ding/data/buffer/tests/test_middleware.py
+++ b/ding/data/buffer/tests/test_middleware.py
@@ -106,6 +106,7 @@ def test_priority():
     assert data[0].meta['priority'] == 3.0
     buffer.delete(data[0].index)
     assert buffer.count() == N + N - 1
+    assert len(buffer._middleware[0].buffer_idx) == N + N - 1
     buffer.clear()
     assert buffer.count() == 0