diff --git a/backend/services/presence-service/nest-cli.json b/backend/services/presence-service/nest-cli.json
new file mode 100644
index 00000000..f9aa683b
--- /dev/null
+++ b/backend/services/presence-service/nest-cli.json
@@ -0,0 +1,8 @@
+{
+  "$schema": "https://json.schemastore.org/nest-cli",
+  "collection": "@nestjs/schematics",
+  "sourceRoot": "src",
+  "compilerOptions": {
+    "deleteOutDir": true
+  }
+}
diff --git a/backend/services/presence-service/package.json b/backend/services/presence-service/package.json
new file mode 100644
index 00000000..9c0a32af
--- /dev/null
+++ b/backend/services/presence-service/package.json
@@ -0,0 +1,57 @@
+{
+  "name": "presence-service",
+  "version": "1.0.0",
+  "description": "RWA Presence Service - User Presence & DAU Tracking",
+  "author": "RWA Team",
+  "private": true,
+  "license": "UNLICENSED",
+  "prisma": {
+    "schema": "prisma/schema.prisma"
+  },
+  "scripts": {
+    "build": "nest build",
+    "format": "prettier --write \"src/**/*.ts\"",
+    "start": "nest start",
+    "start:dev": "nest start --watch",
+    "start:debug": "nest start --debug --watch",
+    "start:prod": "node dist/main",
+    "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
+    "prisma:generate": "prisma generate",
+    "prisma:migrate": "prisma migrate dev",
+    "prisma:migrate:prod": "prisma migrate deploy",
+    "prisma:studio": "prisma studio"
+  },
+  "dependencies": {
+    "@nestjs/common": "^10.0.0",
+    "@nestjs/config": "^3.1.1",
+    "@nestjs/core": "^10.0.0",
+    "@nestjs/platform-express": "^10.0.0",
+    "@nestjs/schedule": "^4.0.0",
+    "@nestjs/swagger": "^7.1.17",
+    "@prisma/client": "^5.7.0",
+    "class-transformer": "^0.5.1",
+    "class-validator": "^0.14.0",
+    "ioredis": "^5.3.2",
+    "reflect-metadata": "^0.1.13",
+    "rxjs": "^7.8.1"
+  },
+  "devDependencies": {
+    "@nestjs/cli": "^10.0.0",
+    "@nestjs/schematics": "^10.0.0",
+    "@nestjs/testing": "^10.0.0",
+    "@types/express": "^4.17.17",
+    "@types/node": "^20.3.1",
+    "@typescript-eslint/eslint-plugin": "^6.0.0",
+    "@typescript-eslint/parser": "^6.0.0",
+    "eslint": "^8.42.0",
+    "eslint-config-prettier": "^9.0.0",
+    "eslint-plugin-prettier": "^5.0.0",
+    "prettier": "^3.0.0",
+    "prisma": "^5.7.0",
+    "source-map-support": "^0.5.21",
+    "ts-loader": "^9.4.3",
+    "ts-node": "^10.9.1",
+    "tsconfig-paths": "^4.2.0",
+    "typescript": "^5.1.3"
+  }
+}
diff --git a/backend/services/presence-service/prisma/schema.prisma b/backend/services/presence-service/prisma/schema.prisma
new file mode 100644
index 00000000..14640ee0
--- /dev/null
+++ b/backend/services/presence-service/prisma/schema.prisma
@@ -0,0 +1,92 @@
+// =============================================================================
+// Presence Service - Prisma Schema
+// =============================================================================
+
+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+// =============================================================================
+// Heartbeat (在线心跳记录)
+// =============================================================================
+
+model Heartbeat {
+  id          String   @id @default(uuid())
+  installId   String   // 设备唯一安装ID
+  sessionId   String   // 会话ID
+  userId      String?  // 用户ID (可选，未登录时为null)
+  timestamp   DateTime // 心跳时间戳
+  createdAt   DateTime @default(now())
+
+  @@index([installId, timestamp])
+  @@index([userId, timestamp])
+  @@index([sessionId])
+  @@index([timestamp])
+  @@map("heartbeats")
+}
+
+// =============================================================================
+// Daily Active Users (DAU 日活统计)
+// =============================================================================
+
+model DailyActiveUser {
+  id        String   @id @default(uuid())
+  date      DateTime @db.Date // 统计日期 (YYYY-MM-DD)
+  installId String   // 设备唯一安装ID
+  userId    String?  // 用户ID (可选)
+  firstSeen DateTime // 当日首次出现时间
+  lastSeen  DateTime // 当日最后出现时间
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@unique([date, installId])
+  @@index([date])
+  @@index([userId, date])
+  @@map("daily_active_users")
+}
+
+// =============================================================================
+// Online Presence (实时在线状态)
+// 使用 Redis 存储，此表仅用于历史记录
+// =============================================================================
+
+model OnlineSession {
+  id          String    @id @default(uuid())
+  installId   String    // 设备唯一安装ID
+  sessionId   String    @unique // 会话ID
+  userId      String?   // 用户ID (可选)
+  startTime   DateTime  // 会话开始时间
+  lastHeartbeat DateTime // 最后心跳时间
+  endTime     DateTime? // 会话结束时间 (null表示仍在线)
+  duration    Int?      // 会话时长 (秒)
+  createdAt   DateTime  @default(now())
+  updatedAt   DateTime  @updatedAt
+
+  @@index([installId])
+  @@index([userId])
+  @@index([sessionId])
+  @@index([startTime])
+  @@map("online_sessions")
+}
+
+// =============================================================================
+// DAU Statistics (DAU 统计汇总)
+// =============================================================================
+
+model DauStatistics {
+  id            String   @id @default(uuid())
+  date          DateTime @unique @db.Date // 统计日期
+  totalDau      Int      // 总DAU (按installId去重)
+  uniqueUsers   Int      // 唯一用户数 (按userId去重, 不含匿名)
+  anonymousUsers Int     // 匿名用户数 (userId为null)
+  createdAt     DateTime @default(now())
+  updatedAt     DateTime @updatedAt
+
+  @@index([date])
+  @@map("dau_statistics")
+}
diff --git a/backend/services/presence-service/tsconfig.json b/backend/services/presence-service/tsconfig.json
new file mode 100644
index 00000000..bd3c3946
--- /dev/null
+++ b/backend/services/presence-service/tsconfig.json
@@ -0,0 +1,24 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "declaration": true,
+    "removeComments": true,
+    "emitDecoratorMetadata": true,
+    "experimentalDecorators": true,
+    "allowSyntheticDefaultImports": true,
+    "target": "ES2021",
+    "sourceMap": true,
+    "outDir": "./dist",
+    "baseUrl": "./",
+    "incremental": true,
+    "skipLibCheck": true,
+    "strictNullChecks": true,
+    "noImplicitAny": true,
+    "strictBindCallApply": true,
+    "forceConsistentCasingInFileNames": true,
+    "noFallthroughCasesInSwitch": true,
+    "paths": {
+      "@/*": ["src/*"]
+    }
+  }
+}