diff --git a/src/core/splitters/registry.py b/src/core/splitters/registry.py
index 442ec4a..70a1006 100644
--- a/src/core/splitters/registry.py
+++ b/src/core/splitters/registry.py
@@ -1,22 +1,69 @@
-"""分块器注册表 — 按文件后缀名路由到对应 Splitter."""
+"""Splitter 注册表 — 按文件扩展名自动选择分块器."""
+from pathlib import Path
+from src.core.splitters.base import Splitter
 
-SUPPORTED_SUFFIXES: dict[str, str] = {
+# 扩展名 → Splitter 类名映射
+_DEFAULT_MAP: dict[str, str] = {
     ".md": "markdown",
+    ".markdown": "markdown",
     ".txt": "text",
-    ".html": "html",
     ".pdf": "pdf",
+    ".html": "html",
+    ".htm": "html",
 }
 
-_registry: dict[str, type] = {}
+# 所有支持的扩展名集合（供外部遍历文件使用）
+SUPPORTED_SUFFIXES = frozenset(_DEFAULT_MAP.keys())
+
+# 用户可注册自定义 Splitter
+_custom_registry: dict[str, type[Splitter]] = {}
 
 
-def register_splitter(name: str, splitter_cls: type) -> None:
-    """注册一个分块器."""
-    _registry[name] = splitter_cls
+def register_splitter(ext: str, splitter_cls: type[Splitter]) -> None:
+    """注册自定义 Splitter 类."""
+    ext = ext.lower() if ext.startswith(".") else f".{ext}"
+    _custom_registry[ext] = splitter_cls
 
 
-def get_splitter(name: str):
-    """获取已注册的分块器类."""
-    if name not in _registry:
-        raise ValueError(f"未注册的分块器: {name}")
-    return _registry[name]
+def get_splitter(
+    file_path: str,
+    max_size: int = 1000,
+    overlap: int = 100,
+) -> Splitter:
+    """根据文件扩展名自动选择 Splitter，未匹配回退到 TextSplitter.
+
+    Args:
+        file_path: 文件路径（用于提取扩展名）
+        max_size: 分块最大字符数
+        overlap: 相邻块重叠字符数
+
+    Returns:
+        对应格式的 Splitter 实例
+    """
+    ext = Path(file_path).suffix.lower()
+
+    # 优先查用户自定义注册
+    if ext in _custom_registry:
+        return _custom_registry[ext](max_size=max_size, overlap=overlap)
+
+    kind = _DEFAULT_MAP.get(ext, "text")
+
+    if kind == "markdown":
+        from src.core.splitters.markdown import MarkdownSplitter
+        return MarkdownSplitter(max_size=max_size, overlap=overlap)
+
+    if kind == "text":
+        from src.core.splitters.text import TextSplitter
+        return TextSplitter(max_size=max_size, overlap=overlap)
+
+    if kind == "pdf":
+        from src.core.splitters.pdf import PDFSplitter
+        return PDFSplitter(max_size=max_size, overlap=overlap)
+
+    if kind == "html":
+        from src.core.splitters.html import HTMLSplitter
+        return HTMLSplitter(max_size=max_size, overlap=overlap)
+
+    # 回退
+    from src.core.splitters.text import TextSplitter
+    return TextSplitter(max_size=max_size, overlap=overlap)
diff --git a/src/core/splitters/text.py b/src/core/splitters/text.py
index 4d351a0..41f4b31 100644
--- a/src/core/splitters/text.py
+++ b/src/core/splitters/text.py
@@ -1,9 +1,9 @@
-"""纯文本文档分块器（待实现）."""
+"""纯文本分块器 — 按段落双换行切分."""
 from src.core.splitters.base import BaseTextSplitter
 
 
 class TextSplitter(BaseTextSplitter):
-    """纯文本分块器 — 按段落和字符边界拆分."""
+    """纯文本分块器：按 \n\n 切段落，超长按标点硬切."""
 
     def split(self, text: str, source_file: str = "") -> list[dict]:
         if not text.strip():
@@ -11,6 +11,7 @@ class TextSplitter(BaseTextSplitter):
 
         chunks = self._split_by_paragraphs(text)
         for i, chunk in enumerate(chunks):
-            chunk["source_file"] = source_file or chunk.get("source_file", "")
+            chunk["source_file"] = source_file
             chunk["chunk_index"] = i
+
         return chunks