diff --git a/internal/service/admin.go b/internal/service/admin.go
new file mode 100644
index 0000000..4e23e8c
--- /dev/null
+++ b/internal/service/admin.go
@@ -0,0 +1,53 @@
+package service
+
+import (
+	"errors"
+
+	"gotest/internal/model"
+	"gotest/internal/repository"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// AdminService 管理员服务，负责管理员检查与初始化
+type AdminService struct {
+	userRepo *repository.UserRepository
+}
+
+// NewAdminService 创建管理员服务实例
+func NewAdminService(userRepo *repository.UserRepository) *AdminService {
+	return &AdminService{userRepo: userRepo}
+}
+
+// CheckAdmin 检查管理员是否已存在
+func (s *AdminService) CheckAdmin() (bool, error) {
+	count, err := s.userRepo.Count()
+	if err != nil {
+		return false, err
+	}
+	return count > 0, nil
+}
+
+// InitAdmin 初始化管理员账号（仅在无任何用户时允许）
+func (s *AdminService) InitAdmin(username, password string) error {
+	// 已存在用户时禁止初始化
+	count, err := s.userRepo.Count()
+	if err != nil {
+		return err
+	}
+	if count > 0 {
+		return errors.New("系统已初始化，禁止重复操作")
+	}
+
+	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return err
+	}
+
+	return s.userRepo.Create(&model.User{
+		Username: username,
+		Password: string(hashedPassword),
+		Role:     "admin",
+		Status:   1,
+	})
+}