diff --git a/br/pkg/task/stream.go b/br/pkg/task/stream.go
index 8596eb89d6974..ced88b27e3f3d 100644
--- a/br/pkg/task/stream.go
+++ b/br/pkg/task/stream.go
@@ -480,6 +480,12 @@ func KeepGcDisabled(g glue.Glue, store kv.Storage) (RestoreFunc, error) {
 		return nil, errors.Trace(err)
 	}
 
+	// If the oldRatio is negative, which is not normal status.
+	// It should set default value "1.1" after PiTR finished.
+	if strings.HasPrefix(oldRatio, "-") {
+		oldRatio = "1.1"
+	}
+
 	return func() error {
 		return utils.SetGcRatio(execCtx, oldRatio)
 	}, nil