diff --git a/.woodpecker/build.yml b/.woodpecker/build.yml
index 264c7c3..9f0b86e 100644
--- a/.woodpecker/build.yml
+++ b/.woodpecker/build.yml
@@ -77,6 +77,7 @@ steps:
       docker run -d --name cpdaily-xiaozhushou-new \
         --restart unless-stopped \
         --network likedream-net \
+        -e TZ=Asia/Shanghai \
         -p $PORT_STANDBY:8093 \
         -v /opt/cpdaily-xiaozhushou/config.toml:/app/config.toml:ro \
         cpdaily-xiaozhushou:$IMAGE_TAG
@@ -126,6 +127,7 @@ steps:
       docker run -d --name cpdaily-xiaozhushou \
         --restart unless-stopped \
         --network likedream-net \
+        -e TZ=Asia/Shanghai \
         -p $PORT_ACTIVE:8093 \
         -v /opt/cpdaily-xiaozhushou/config.toml:/app/config.toml:ro \
         cpdaily-xiaozhushou:$IMAGE_TAG
diff --git a/Dockerfile b/Dockerfile
index 147f60c..44241ed 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -24,6 +24,8 @@ RUN go build -ldflags="-s -w" -o server ./cmd/server/
 # ============================================================
 FROM alpine:latest
 RUN apk add --no-cache ca-certificates tzdata
+# 时区固定为北京时间（tzdata 已安装；进程层 main.go 另有 time.Local 兜底）
+ENV TZ=Asia/Shanghai
 COPY --from=backend-builder /build/server /app/server
 COPY --from=frontend-builder /build/dist /app/dist
 WORKDIR /app
diff --git a/backed/cmd/server/main.go b/backed/cmd/server/main.go
index 3d61d39..b31ff6b 100644
--- a/backed/cmd/server/main.go
+++ b/backed/cmd/server/main.go
@@ -23,6 +23,16 @@ func main() {
 		log.Fatalf("加载配置失败: %v", err)
 	}
 
+	// 全局时区固定为中国标准时间（必须在 database.Init 之前设置：
+	// DSN 的 loc=Local 跟随 time.Local，影响数据库 datetime 读写序列化）。
+	// 运行镜像若不设 TZ 默认 UTC，会让所有记录/查询/统计/输出偏移 8 小时
+	// （前端展示为"美国时间"），每月 1 日与每日 0-8 点的边界计算也会错位。
+	loc, err := time.LoadLocation("Asia/Shanghai")
+	if err != nil {
+		log.Fatalf("加载时区 Asia/Shanghai 失败: %v", err)
+	}
+	time.Local = loc
+
 	// 连接数据库
 	database.Init()
 
diff --git a/backed/internal/handler/pending_school.go b/backed/internal/handler/pending_school.go
index 7501997..81081db 100644
--- a/backed/internal/handler/pending_school.go
+++ b/backed/internal/handler/pending_school.go
@@ -196,7 +196,9 @@ func ReportFailedLogin(c *fiber.Ctx) error {
 	}
 
 	// 1. 检查该校是否有今天登录过的账号（说明学校可正常使用，忽略本次报告）
-	today := time.Now().Truncate(24 * time.Hour)
+	// 注意：Truncate(24h) 按 UTC 午夜截断会偏移 8 小时，必须按北京时间当日 0 点
+	now := time.Now()
+	today := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
 	var todayLoginCount int64
 	database.DB.Model(&model.SysUser{}).
 		Where("school_id = ? AND last_login_at >= ?", req.SchoolID, today).
diff --git a/deploy/docker-compose.yml b/deploy/docker-compose.yml
index e8155d2..16e43af 100644
--- a/deploy/docker-compose.yml
+++ b/deploy/docker-compose.yml
@@ -5,6 +5,8 @@ services:
     restart: unless-stopped
     ports:
       - "8884:8093"
+    environment:
+      - TZ=Asia/Shanghai
     volumes:
       - /opt/cpdaily-xiaozhushou/config.toml:/app/config.toml:ro
     networks: