diff --git a/qlib/finco/tpl/sl/workflow_config.yaml b/qlib/finco/tpl/sl/workflow_config.yaml
index 4c6c4821f..f992a3758 100644
--- a/qlib/finco/tpl/sl/workflow_config.yaml
+++ b/qlib/finco/tpl/sl/workflow_config.yaml
@@ -10,7 +10,7 @@ data_handler_config: &data_handler_config
     fit_start_time: 2008-01-01
     fit_end_time: 2014-12-31
     instruments: *market
-    label: "Ref($close, -21) / Ref($close, -1) - 1"
+    label: ["Ref($close, -21) / Ref($close, -1) - 1"]
     infer_processors:
         - class: RobustZScoreNorm
           kwargs: