diff --git a/backend/internal/integrations/sms/aliyun.go b/backend/internal/integrations/sms/aliyun.go
index 20ea5fb..8afe13d 100644
--- a/backend/internal/integrations/sms/aliyun.go
+++ b/backend/internal/integrations/sms/aliyun.go
@@ -81,16 +81,21 @@ func (p *AliyunProvider) SendLoginCode(ctx context.Context, phone string, code s
 
 	resultCode := dara.StringValue(resp.Body.Code)
 	if resultCode != "OK" {
+		resultMessage := dara.StringValue(resp.Body.Message)
 		if p.log != nil {
 			p.log.Warn(
 				"aliyun sms rejected",
 				zap.String("phone", maskPhone(phone)),
 				zap.String("request_id", dara.StringValue(resp.Body.RequestId)),
 				zap.String("code", resultCode),
-				zap.String("message", dara.StringValue(resp.Body.Message)),
+				zap.String("message", resultMessage),
 			)
 		}
-		return fmt.Errorf("aliyun sms rejected: %s", resultCode)
+		providerErr := &ProviderError{Code: resultCode, Message: resultMessage}
+		if resultCode == "isv.BUSINESS_LIMIT_CONTROL" {
+			providerErr.Err = ErrProviderRateLimited
+		}
+		return providerErr
 	}
 
 	if p.log != nil {
diff --git a/backend/internal/integrations/sms/provider.go b/backend/internal/integrations/sms/provider.go
index 4ff4408..7fd1fef 100644
--- a/backend/internal/integrations/sms/provider.go
+++ b/backend/internal/integrations/sms/provider.go
@@ -3,10 +3,38 @@ package sms
 import (
 	"context"
 	"errors"
+	"fmt"
 )
 
-var ErrProviderConfigInvalid = errors.New("sms provider config invalid")
+var (
+	ErrProviderConfigInvalid = errors.New("sms provider config invalid")
+	ErrProviderRateLimited   = errors.New("sms provider rate limited")
+)
 
 type Provider interface {
 	SendLoginCode(ctx context.Context, phone string, code string) error
 }
+
+type ProviderError struct {
+	Code    string
+	Message string
+	Err     error
+}
+
+func (e *ProviderError) Error() string {
+	if e.Message != "" {
+		return fmt.Sprintf("sms provider rejected: %s: %s", e.Code, e.Message)
+	}
+	if e.Code != "" {
+		return fmt.Sprintf("sms provider rejected: %s", e.Code)
+	}
+	return "sms provider rejected"
+}
+
+func (e *ProviderError) Unwrap() error {
+	return e.Err
+}
+
+func IsProviderRateLimited(err error) bool {
+	return errors.Is(err, ErrProviderRateLimited)
+}
diff --git a/backend/internal/integrations/sms/provider_test.go b/backend/internal/integrations/sms/provider_test.go
new file mode 100644
index 0000000..a2f4bdf
--- /dev/null
+++ b/backend/internal/integrations/sms/provider_test.go
@@ -0,0 +1,29 @@
+package sms
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestIsProviderRateLimited(t *testing.T) {
+	err := &ProviderError{
+		Code:    "isv.BUSINESS_LIMIT_CONTROL",
+		Message: "触发小时级流控Permits:5",
+		Err:     ErrProviderRateLimited,
+	}
+
+	if !IsProviderRateLimited(err) {
+		t.Fatalf("expected provider rate limit error")
+	}
+	if !errors.Is(err, ErrProviderRateLimited) {
+		t.Fatalf("expected errors.Is to match provider rate limit")
+	}
+}
+
+func TestProviderErrorMessage(t *testing.T) {
+	err := &ProviderError{Code: "isv.INVALID_PARAMETERS", Message: "参数错误"}
+
+	if got := err.Error(); got != "sms provider rejected: isv.INVALID_PARAMETERS: 参数错误" {
+		t.Fatalf("unexpected error message: %s", got)
+	}
+}
diff --git a/backend/internal/modules/auth/service.go b/backend/internal/modules/auth/service.go
index ffca128..17f696f 100644
--- a/backend/internal/modules/auth/service.go
+++ b/backend/internal/modules/auth/service.go
@@ -25,6 +25,12 @@ var (
 	ErrUserDisabled          = errors.New("user disabled")
 )
 
+const (
+	smsLoginCooldown     = 60 * time.Second
+	smsLoginHourlyLimit  = 5
+	smsLoginHourlyWindow = time.Hour
+)
+
 type Service struct {
 	users *UserRepository
 	redis *redis.Client
@@ -59,6 +65,15 @@ func (s *Service) SendSMSCode(ctx context.Context, phone string) error {
 		return ErrCodeRateLimited
 	}
 
+	hourlyKey := "sms:hourly:login:" + phone
+	hourlyCount, err := s.redis.Get(ctx, hourlyKey).Int()
+	if err != nil && !errors.Is(err, redis.Nil) {
+		return err
+	}
+	if hourlyCount >= smsLoginHourlyLimit {
+		return ErrCodeRateLimited
+	}
+
 	code, err := randomDigits(6)
 	if err != nil {
 		return err
@@ -71,12 +86,23 @@ func (s *Service) SendSMSCode(ctx context.Context, phone string) error {
 		if s.log != nil {
 			s.log.Warn("sms login code send failed", zap.String("phone", PublicPhone(phone)), zap.Error(err))
 		}
+		if smsprovider.IsProviderRateLimited(err) {
+			pipe := s.redis.TxPipeline()
+			pipe.Set(ctx, cooldownKey, "1", smsLoginCooldown)
+			pipe.Set(ctx, hourlyKey, smsLoginHourlyLimit, smsLoginHourlyWindow)
+			if _, pipeErr := pipe.Exec(ctx); pipeErr != nil {
+				return pipeErr
+			}
+			return ErrCodeRateLimited
+		}
 		return ErrSMSSendFailed
 	}
 
 	pipe := s.redis.TxPipeline()
 	pipe.Set(ctx, codeKey(phone), code, 5*time.Minute)
-	pipe.Set(ctx, cooldownKey, "1", 60*time.Second)
+	pipe.Set(ctx, cooldownKey, "1", smsLoginCooldown)
+	pipe.Incr(ctx, hourlyKey)
+	pipe.Expire(ctx, hourlyKey, smsLoginHourlyWindow)
 	pipe.Incr(ctx, "sms:daily:login:"+phone)
 	pipe.Expire(ctx, "sms:daily:login:"+phone, 24*time.Hour)
 	if _, err := pipe.Exec(ctx); err != nil {