diff --git a/astrbot/core/knowledge_base/chunking/recursive.py b/astrbot/core/knowledge_base/chunking/recursive.py
index 3f4aabb57..3882b0871 100644
--- a/astrbot/core/knowledge_base/chunking/recursive.py
+++ b/astrbot/core/knowledge_base/chunking/recursive.py
@@ -149,8 +149,16 @@ def _split_by_character(
             分割后的文本块列表
 
         """
-        chunk_size = chunk_size or self.chunk_size
-        overlap = overlap or self.chunk_overlap
+        if chunk_size is None:
+            chunk_size = self.chunk_size
+        if overlap is None:
+            overlap = self.chunk_overlap
+        if chunk_size <= 0:
+            raise ValueError("chunk_size must be greater than 0")
+        if overlap < 0:
+            raise ValueError("chunk_overlap must be non-negative")
+        if overlap >= chunk_size:
+            raise ValueError("chunk_overlap must be less than chunk_size")
         result = []
         for i in range(0, len(text), chunk_size - overlap):
             end = min(i + chunk_size, len(text))