diff --git a/app/agents/__init__.py b/app/agents/__init__.py
index 49b8c66..9c99e07 100644
--- a/app/agents/__init__.py
+++ b/app/agents/__init__.py
@@ -1,4 +1,4 @@
-# app/agents/__init__.py
 from .classification_agent import agent_classify_document_from_image
 from .receipt_agent import agent_extract_receipt_info
-from .invoice_agent import agent_extract_invoice_info
\ No newline at end of file
+from .invoice_agent import agent_extract_invoice_info
+from .vectorization_agent import agent_vectorize_and_store
\ No newline at end of file
diff --git a/app/agents/vectorization_agent.py b/app/agents/vectorization_agent.py
index 983e568..2677a75 100644
--- a/app/agents/vectorization_agent.py
+++ b/app/agents/vectorization_agent.py
@@ -1,38 +1,43 @@
 # app/agents/vectorization_agent.py
 from langchain.text_splitter import RecursiveCharacterTextSplitter
-from ..core.vector_store import vector_store, embedding_model
+from langchain_openai import OpenAIEmbeddings
+embedding_model = OpenAIEmbeddings(model="text-embedding-3-small")
+import chromadb
+
+client = chromadb.PersistentClient(path="./chroma_db")
+vector_store = client.get_or_create_collection(name="documents")
 
-# Initialize the text splitter to divide long documents into smaller chunks
 text_splitter = RecursiveCharacterTextSplitter(
-    chunk_size=500,
-    chunk_overlap=50,
+    chunk_size=1000,
+    chunk_overlap=100,
 )
 
-def agent_vectorize_and_store(doc_id: str, text: str, category: str):
-    """Agent 4: Vectorization and Storage (Real Implementation)"""
-    print(f"--- [Agent 4] Vectorizing document (ID: {doc_id})...")
+def agent_vectorize_and_store(doc_id: str, text: str, category: str, language: str):
+    """
+    Agent 4: Vectorizes a document and stores it in ChromaDB.
+    """
+    print(f"--- [Background Task] Starting vectorization (ID: {doc_id})...")
 
-    # 1. Split the document text into chunks
-    chunks = text_splitter.split_text(text)
-    print(f"--- [Agent 4] Document split into {len(chunks)} chunks.")
-
-    if not chunks:
-        print(f"--- [Agent 4] Document is empty, skipping vectorization.")
+    try:
         return
 
-    # 2. Create a unique ID and metadata for each chunk
-    chunk_ids = [f"{doc_id}_{i}" for i in range(len(chunks))]
-    metadatas = [{"doc_id": doc_id, "category": category, "chunk_number": i} for i in range(len(chunks))]
+        chunks = text_splitter.split_text(text)
+        if not chunks:
+            print(f"--- [Background Task] document {doc_id} has no text to vectorize.")
+            return
 
-    # 3. Use an embedding model to generate vectors for all chunks
-    embeddings = embedding_model.embed_documents(chunks)
+        chunk_ids = [f"{doc_id}_{i}" for i in range(len(chunks))]
+        metadatas = [{"doc_id": doc_id, "category": category, "language": language, "chunk_number": i} for i in
+                     range(len(chunks))]
 
-    # 4. Add the IDs, vectors, metadata, and text chunks to ChromaDB
-    vector_store.add(
-        ids=chunk_ids,
-        embeddings=embeddings,
-        documents=chunks,
-        metadatas=metadatas
-    )
+        embeddings = embedding_model.embed_documents(chunks)
 
-    print(f"--- [Agent 4] document {doc_id} stored in ChromaDB。")
+        vector_store.add(
+            ids=chunk_ids,
+            embeddings=embeddings,
+            documents=chunks,
+            metadatas=metadatas
+        )
+        print(f"--- [Background Task] Document {doc_id} vectorized and stored successfully.")
+    except Exception as e:
+        print(f"--- [background Task] Vectorization failed (ID: {doc_id}): {e}")
diff --git a/app/core/ocr.py b/app/core/ocr.py
new file mode 100644
index 0000000..1e42327
--- /dev/null
+++ b/app/core/ocr.py
@@ -0,0 +1,23 @@
+import pytesseract
+from PIL import Image
+from typing import List
+
+
+def extract_text_from_images(images: List[Image.Image]) -> str:
+    """
+    使用Tesseract OCR从一系列图片中提取并合并所有文本。
+    """
+    print("--- [Core OCR] 正在从图片中提取文本用于向量化...")
+    full_text = []
+    for img in images:
+        try:
+            # lang='chi_sim+eng' 表示同时识别简体中文和英文
+            text = pytesseract.image_to_string(img, lang='chi_sim+eng')
+            full_text.append(text)
+        except Exception as e:
+            print(f"--- [Core OCR] 单页处理失败: {e}")
+            continue
+
+    combined_text = "\n\n--- Page Break ---\n\n".join(full_text)
+    print("--- [Core OCR] 文本提取成功。")
+    return combined_text
diff --git a/app/routers/documents.py b/app/routers/documents.py
index 8d3e9ec..221cdb3 100644
--- a/app/routers/documents.py
+++ b/app/routers/documents.py
@@ -1,8 +1,6 @@
-# app/routers/documents.py
 import uuid
 import mimetypes
-import base64
-from fastapi import APIRouter, UploadFile, File, HTTPException
+from fastapi import APIRouter, UploadFile, File, HTTPException, BackgroundTasks
 from typing import Dict, Any, List
 from fastapi.concurrency import run_in_threadpool
 from PIL import Image
@@ -10,6 +8,7 @@ from io import BytesIO
 
 from .. import agents
 from ..core.pdf_processor import convert_pdf_to_images, image_to_base64_str
+from ..core.ocr import extract_text_from_images
 
 # Create an APIRouter instance
 router = APIRouter(
@@ -46,8 +45,12 @@ async def multimodal_process_pipeline(doc_id: str, image: Image.Image, page_num:
     db_results[final_result["doc_id"]] = final_result
     return final_result
 
-@router.post("/process", summary="upload and process a document")
-async def upload_and_process_document(file: UploadFile = File(...)):
+
+@router.post("/process", summary="Upload and Process Document")
+async def upload_and_process_document(
+        file: UploadFile = File(...),
+        background_tasks: BackgroundTasks = BackgroundTasks()
+):
     if not file.filename:
         raise HTTPException(status_code=400, detail="No file provided.")
 
@@ -57,7 +60,7 @@ async def upload_and_process_document(file: UploadFile = File(...)):
 
     try:
         file_type = mimetypes.guess_type(file.filename)[0]
-        print(f"File type: {file_type}")
+        print(f"Detected file type: {file_type}")
 
         images: List[Image.Image] = []
         if file_type == 'application/pdf':
@@ -84,18 +87,28 @@ async def upload_and_process_document(file: UploadFile = File(...)):
             elif category == "INVOICE":
                 extraction_result = await agents.agent_extract_invoice_info(images_base64, language)
         else:
-            print(f"The document is classified as '{category}'，skipping extraction。")
+            print(f"Document classified as '{category}'，skipping extraction。")
 
-        # 3. Return a unified result
         final_result = {
             "doc_id": doc_id,
+            "message": "Document processing initiated. Vectorization is running in the background.",
             "page_count": len(images),
             "category": category,
             "language": language,
             "extraction_data": extraction_result.dict() if extraction_result else None,
-            "status": "Processed"
+            "status": "Processing"
         }
-        db_results[doc_id] = final_result
+
+        full_text = await run_in_threadpool(extract_text_from_images, images)
+        background_tasks.add_task(
+            agents.agent_vectorize_and_store,
+            doc_id,
+            full_text,
+            category,
+            language
+        )
+        print("--- [Main] Vectorization job added to background tasks.")
+
         return final_result
 
     except Exception as e:
diff --git a/chroma_db/chroma.sqlite3 b/chroma_db/chroma.sqlite3
new file mode 100644
index 0000000..e43d25f
Binary files /dev/null and b/chroma_db/chroma.sqlite3 differ