diff --git a/.gitignore b/.gitignore
index 70e7625..6ddf0c0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,5 +20,3 @@ server/billai-server
 server/uploads/
 server/outputs/
 *.log
-
-mongo/
\ No newline at end of file
diff --git a/server/repository/mongo/repository.go b/server/repository/mongo/repository.go
new file mode 100644
index 0000000..0ec82da
--- /dev/null
+++ b/server/repository/mongo/repository.go
@@ -0,0 +1,327 @@
+// Package mongo 实现基于 MongoDB 的账单存储
+package mongo
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+
+	"billai-server/config"
+	"billai-server/model"
+	"billai-server/repository"
+)
+
+// Repository MongoDB 账单存储实现
+type Repository struct {
+	client            *mongo.Client
+	db                *mongo.Database
+	rawCollection     *mongo.Collection
+	cleanedCollection *mongo.Collection
+}
+
+// NewRepository 创建 MongoDB 存储实例
+func NewRepository() *Repository {
+	return &Repository{}
+}
+
+// Connect 连接 MongoDB
+func (r *Repository) Connect() error {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	// 创建客户端选项
+	clientOptions := options.Client().ApplyURI(config.Global.MongoURI)
+
+	// 连接 MongoDB
+	client, err := mongo.Connect(ctx, clientOptions)
+	if err != nil {
+		return fmt.Errorf("连接 MongoDB 失败: %w", err)
+	}
+
+	// 测试连接
+	if err := client.Ping(ctx, nil); err != nil {
+		return fmt.Errorf("MongoDB Ping 失败: %w", err)
+	}
+
+	// 设置实例变量
+	r.client = client
+	r.db = client.Database(config.Global.MongoDatabase)
+	r.rawCollection = r.db.Collection(config.Global.MongoRawCollection)
+	r.cleanedCollection = r.db.Collection(config.Global.MongoCleanedCollection)
+
+	fmt.Printf("🍃 MongoDB 连接成功: %s\n", config.Global.MongoDatabase)
+	fmt.Printf("   📄 原始数据集合: %s\n", config.Global.MongoRawCollection)
+	fmt.Printf("   📄 清洗数据集合: %s\n", config.Global.MongoCleanedCollection)
+	return nil
+}
+
+// Disconnect 断开 MongoDB 连接
+func (r *Repository) Disconnect() error {
+	if r.client == nil {
+		return nil
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	if err := r.client.Disconnect(ctx); err != nil {
+		return fmt.Errorf("断开 MongoDB 连接失败: %w", err)
+	}
+
+	fmt.Println("🍃 MongoDB 连接已断开")
+	return nil
+}
+
+// SaveRawBills 保存原始账单数据
+func (r *Repository) SaveRawBills(bills []model.RawBill) (int, error) {
+	if len(bills) == 0 {
+		return 0, nil
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	// 转换为 interface{} 切片
+	docs := make([]interface{}, len(bills))
+	for i, bill := range bills {
+		docs[i] = bill
+	}
+
+	result, err := r.rawCollection.InsertMany(ctx, docs)
+	if err != nil {
+		return 0, fmt.Errorf("插入原始账单失败: %w", err)
+	}
+
+	return len(result.InsertedIDs), nil
+}
+
+// SaveCleanedBills 保存清洗后的账单数据（带去重）
+func (r *Repository) SaveCleanedBills(bills []model.CleanedBill) (saved int, duplicates int, err error) {
+	if len(bills) == 0 {
+		return 0, 0, nil
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	for _, bill := range bills {
+		// 检查是否重复
+		isDup, err := r.CheckCleanedDuplicate(&bill)
+		if err != nil {
+			return saved, duplicates, err
+		}
+		if isDup {
+			duplicates++
+			continue
+		}
+
+		// 插入新记录
+		_, err = r.cleanedCollection.InsertOne(ctx, bill)
+		if err != nil {
+			return saved, duplicates, fmt.Errorf("插入清洗后账单失败: %w", err)
+		}
+		saved++
+	}
+
+	return saved, duplicates, nil
+}
+
+// CheckRawDuplicate 检查原始数据是否重复
+func (r *Repository) CheckRawDuplicate(fieldName, value string) (bool, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	filter := bson.M{"raw_data." + fieldName: value}
+	count, err := r.rawCollection.CountDocuments(ctx, filter)
+	if err != nil {
+		return false, err
+	}
+
+	return count > 0, nil
+}
+
+// CheckCleanedDuplicate 检查清洗后数据是否重复
+func (r *Repository) CheckCleanedDuplicate(bill *model.CleanedBill) (bool, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	var filter bson.M
+
+	if bill.TransactionID != "" {
+		// 优先用交易订单号判断
+		filter = bson.M{"transaction_id": bill.TransactionID}
+	} else {
+		// 回退到 时间+金额+商户 组合判断
+		filter = bson.M{
+			"time":     bill.Time,
+			"amount":   bill.Amount,
+			"merchant": bill.Merchant,
+		}
+	}
+
+	count, err := r.cleanedCollection.CountDocuments(ctx, filter)
+	if err != nil {
+		return false, err
+	}
+
+	return count > 0, nil
+}
+
+// CountRawByField 按字段统计原始数据数量
+func (r *Repository) CountRawByField(fieldName, value string) (int64, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	filter := bson.M{"raw_data." + fieldName: value}
+	return r.rawCollection.CountDocuments(ctx, filter)
+}
+
+// GetCleanedBills 获取清洗后的账单列表
+func (r *Repository) GetCleanedBills(filter map[string]interface{}) ([]model.CleanedBill, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	// 转换 filter
+	bsonFilter := bson.M{}
+	for k, v := range filter {
+		bsonFilter[k] = v
+	}
+
+	// 按时间倒序排列
+	opts := options.Find().SetSort(bson.D{{Key: "time", Value: -1}})
+
+	cursor, err := r.cleanedCollection.Find(ctx, bsonFilter, opts)
+	if err != nil {
+		return nil, fmt.Errorf("查询账单失败: %w", err)
+	}
+	defer cursor.Close(ctx)
+
+	var bills []model.CleanedBill
+	if err := cursor.All(ctx, &bills); err != nil {
+		return nil, fmt.Errorf("解析账单数据失败: %w", err)
+	}
+
+	return bills, nil
+}
+
+// GetCleanedBillsPaged 获取清洗后的账单列表（带分页）
+func (r *Repository) GetCleanedBillsPaged(filter map[string]interface{}, page, pageSize int) ([]model.CleanedBill, int64, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	// 转换 filter
+	bsonFilter := bson.M{}
+	for k, v := range filter {
+		bsonFilter[k] = v
+	}
+
+	// 计算总数
+	total, err := r.cleanedCollection.CountDocuments(ctx, bsonFilter)
+	if err != nil {
+		return nil, 0, fmt.Errorf("统计账单数量失败: %w", err)
+	}
+
+	// 计算跳过数量
+	skip := int64((page - 1) * pageSize)
+
+	// 查询选项：分页 + 按时间倒序
+	opts := options.Find().
+		SetSort(bson.D{{Key: "time", Value: -1}}).
+		SetSkip(skip).
+		SetLimit(int64(pageSize))
+
+	cursor, err := r.cleanedCollection.Find(ctx, bsonFilter, opts)
+	if err != nil {
+		return nil, 0, fmt.Errorf("查询账单失败: %w", err)
+	}
+	defer cursor.Close(ctx)
+
+	var bills []model.CleanedBill
+	if err := cursor.All(ctx, &bills); err != nil {
+		return nil, 0, fmt.Errorf("解析账单数据失败: %w", err)
+	}
+
+	return bills, total, nil
+}
+
+// GetBillsAggregate 获取账单聚合统计（总收入、总支出）
+func (r *Repository) GetBillsAggregate(filter map[string]interface{}) (totalExpense float64, totalIncome float64, err error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	// 转换 filter
+	bsonFilter := bson.M{}
+	for k, v := range filter {
+		bsonFilter[k] = v
+	}
+
+	// 使用聚合管道按 income_expense 分组统计金额
+	pipeline := mongo.Pipeline{
+		{{Key: "$match", Value: bsonFilter}},
+		{{Key: "$group", Value: bson.D{
+			{Key: "_id", Value: "$income_expense"},
+			{Key: "total", Value: bson.D{{Key: "$sum", Value: "$amount"}}},
+		}}},
+	}
+
+	cursor, err := r.cleanedCollection.Aggregate(ctx, pipeline)
+	if err != nil {
+		return 0, 0, fmt.Errorf("聚合统计失败: %w", err)
+	}
+	defer cursor.Close(ctx)
+
+	// 解析结果
+	var results []struct {
+		ID    string  `bson:"_id"`
+		Total float64 `bson:"total"`
+	}
+	if err := cursor.All(ctx, &results); err != nil {
+		return 0, 0, fmt.Errorf("解析聚合结果失败: %w", err)
+	}
+
+	for _, result := range results {
+		switch result.ID {
+		case "支出":
+			totalExpense = result.Total
+		case "收入":
+			totalIncome = result.Total
+		}
+	}
+
+	return totalExpense, totalIncome, nil
+}
+
+// GetBillsNeedReview 获取需要复核的账单
+func (r *Repository) GetBillsNeedReview() ([]model.CleanedBill, error) {
+	filter := map[string]interface{}{
+		"review_level": bson.M{"$in": []string{"HIGH", "LOW"}},
+	}
+	return r.GetCleanedBills(filter)
+}
+
+// GetClient 获取 MongoDB 客户端（用于兼容旧代码）
+func (r *Repository) GetClient() *mongo.Client {
+	return r.client
+}
+
+// GetDB 获取数据库实例（用于兼容旧代码）
+func (r *Repository) GetDB() *mongo.Database {
+	return r.db
+}
+
+// GetRawCollection 获取原始数据集合（用于兼容旧代码）
+func (r *Repository) GetRawCollection() *mongo.Collection {
+	return r.rawCollection
+}
+
+// GetCleanedCollection 获取清洗后数据集合（用于兼容旧代码）
+func (r *Repository) GetCleanedCollection() *mongo.Collection {
+	return r.cleanedCollection
+}
+
+// 确保 Repository 实现了 repository.BillRepository 接口
+var _ repository.BillRepository = (*Repository)(nil)