diff --git a/backend/internal/service/facemask.go b/backend/internal/service/facemask.go
index 34adbd0..7cdf9ad 100644
--- a/backend/internal/service/facemask.go
+++ b/backend/internal/service/facemask.go
@@ -278,13 +278,17 @@ func applyFaceNotice(b []byte) ([]byte, error) {
 // drawStocking 在给定区域上盖一层黑丝网眼：细密的深色网格线，遮住五官细节但保留轮廓。
 func drawStocking(dst *image.RGBA, r image.Rectangle) {
 	r = r.Intersect(dst.Bounds())
-	step := r.Dx() / 18
-	if step < 4 {
-		step = 4
+	step := r.Dx() / 24
+	if step < 3 {
+		step = 3
+	}
+	line := step / 2
+	if line < 1 {
+		line = 1
 	}
 	for y := r.Min.Y; y < r.Max.Y; y++ {
 		for x := r.Min.X; x < r.Max.X; x++ {
-			if (x-r.Min.X)%step != 0 && (y-r.Min.Y)%step != 0 {
+			if (x-r.Min.X)%step >= line && (y-r.Min.Y)%step >= line {
 				continue
 			}
 			c := dst.RGBAAt(x, y)
@@ -295,3 +299,7 @@ func drawStocking(dst *image.RGBA, r image.Rectangle) {
 		}
 	}
 }
+
+// faceMaskPromptNote 附加到 Seedance 提示词后：告知模型参考图脸部的网格线只是打码，
+// 需要忽略网格本身并完整还原面部细节。
+const faceMaskPromptNote = "参考图人物脸部覆盖的细密网格线仅为隐私打码，不是人物本身的特征：生成时请完全忽略这些网格线，不要在画面中出现任何网格、方格、纹理或遮挡；请依据参考图的五官轮廓完整还原人物真实面孔，保留妆容、眉眼、发型、发饰、耳饰、头冠等一切面部与头部装饰细节，人物面部必须清晰完整、前后镜头保持一致。"
diff --git a/backend/internal/service/v1.go b/backend/internal/service/v1.go
index dd4b358..feb33e3 100644
--- a/backend/internal/service/v1.go
+++ b/backend/internal/service/v1.go
@@ -1803,7 +1803,9 @@ func (s *V1Service) generateAdobeVideo(ctx context.Context, eventID string, mode
 	}
 	// Seedance 参考图先做人脸打码再上传；检不出人脸就沿用原图，
 	// 检测器不可用则直接报错，避免把未打码的人脸传给上游。
+	prompt := in.Prompt
 	if isSeedanceModel(modelItem.ID) {
+		faceMasked := false
 		for i, r := range imgRefs {
 			marked, mErr := applyFaceNotice(r)
 			if errors.Is(mErr, ErrNoFaceDetected) {
@@ -1813,6 +1815,10 @@ func (s *V1Service) generateAdobeVideo(ctx context.Context, eventID string, mode
 				return nil, "", fmt.Errorf("face mask: %w", mErr)
 			}
 			imgRefs[i] = marked
+			faceMasked = true
+		}
+		if faceMasked {
+			prompt = strings.TrimSpace(prompt + "\n\n" + faceMaskPromptNote)
 		}
 	}
 
@@ -1859,7 +1865,7 @@ func (s *V1Service) generateAdobeVideo(ctx context.Context, eventID string, mode
 			}
 			audioBlobIDs = append(audioBlobIDs, id)
 		}
-		bytes, meta, genErr := s.adobe.GenerateVideo(ctx, token.Value, engine, in.Prompt, aspectRatio, durationSeconds, resolution, referenceMode, upstreamModel, blobIDs, videoBlobIDs, audioBlobIDs, downloadResult)
+		bytes, meta, genErr := s.adobe.GenerateVideo(ctx, token.Value, engine, prompt, aspectRatio, durationSeconds, resolution, referenceMode, upstreamModel, blobIDs, videoBlobIDs, audioBlobIDs, downloadResult)
 		if genErr == nil {
 			videoURL = strings.TrimSpace(stringValue(meta["video_url"]))
 		}