diff --git a/rag_indexer/index_builder.py b/rag_indexer/index_builder.py
index 8970351..b60319e 100644
--- a/rag_indexer/index_builder.py
+++ b/rag_indexer/index_builder.py
@@ -71,6 +71,9 @@ class IndexBuilderConfig:
 
     # 其他切分器参数（当 splitter_type 非父子块时使用）
     extra_splitter_kwargs: Dict[str, Any] = field(default_factory=dict)
+    
+    # 混合检索支持（默认 False，完全兼容）
+    enable_sparse: bool = False
 
 # ---------- 索引构建器 ----------
 class IndexBuilder:
@@ -116,10 +119,27 @@ class IndexBuilder:
             self.embeddings = self.embedder.as_langchain_embeddings()
 
         # 初始化向量存储
-        self.vector_store = QdrantVectorStore(
-            collection_name=config.collection_name,
-            embeddings=self.embeddings if self.embedder is None else None,
-        )
+        # 默认 enable_sparse=False，完全兼容现有代码
+        # 若需要启用混合检索，请先安装 fastembed，然后设置 enable_sparse=True
+        qdrant_kwargs = {
+            "collection_name": config.collection_name,
+        }
+        
+        if self.config.enable_sparse:
+            try:
+                from langchain_qdrant import FastEmbedSparse, RetrievalMode
+                qdrant_kwargs["sparse_embedding"] = FastEmbedSparse(model_name="Qdrant/bm25")
+                qdrant_kwargs["retrieval_mode"] = RetrievalMode.HYBRID
+                logger.info("✅ 稀疏向量支持已启用")
+            except ImportError:
+                logger.warning("⚠️ fastembed 未安装，无法启用稀疏向量，继续使用纯稠密")
+            except Exception as e:
+                logger.warning(f"⚠️ 稀疏向量初始化失败: {e}，继续使用纯稠密")
+        
+        if self.embedder is None:
+            qdrant_kwargs["embedding"] = self.embeddings
+        
+        self.vector_store = QdrantVectorStore(**qdrant_kwargs)
 
         # 根据切分类型初始化相关组件
         self._init_splitters_and_retriever()
diff --git a/rag_indexer/requirements.txt b/rag_indexer/requirements.txt
index b7e65d4..1b4460e 100644
--- a/rag_indexer/requirements.txt
+++ b/rag_indexer/requirements.txt
@@ -14,6 +14,8 @@ tiktoken>=0.12.0
 
 # Vector DB
 qdrant-client==1.17.1
+# 可选：用于稀疏向量支持
+# fastembed>=0.3.0
 
 # HTTP
 httpx==0.28.1