diff --git a/backend/internal/domain/constants.go b/backend/internal/domain/constants.go
index d8604abd..53658270 100644
--- a/backend/internal/domain/constants.go
+++ b/backend/internal/domain/constants.go
@@ -94,8 +94,9 @@ var DefaultAntigravityModelMapping = map[string]string{
 	"gemini-3-pro-low":   "gemini-3.1-pro-low",
 	"gemini-3-pro-image": "gemini-3-pro-image",
 	// Gemini 3.1 透传
-	"gemini-3.1-pro-high": "gemini-3.1-pro-high",
-	"gemini-3.1-pro-low":  "gemini-3.1-pro-low",
+	"gemini-3.1-pro-high":    "gemini-3.1-pro-high",
+	"gemini-3.1-pro-low":     "gemini-3.1-pro-low",
+	"gemini-3.1-pro-preview": "gemini-3.1-pro-high",
 	// Gemini 3 preview 映射
 	"gemini-3-flash-preview":     "gemini-3-flash",
 	"gemini-3-pro-preview":       "gemini-3.1-pro-high",