diff --git a/pkg/workflow/tasks/custom/task.go b/pkg/workflow/tasks/custom/task.go
index 10da34a08..1820a80f2 100644
--- a/pkg/workflow/tasks/custom/task.go
+++ b/pkg/workflow/tasks/custom/task.go
@@ -109,7 +109,7 @@ func (t *TaskLoader) makeTaskGenerator(templ string) (wfTypes.TaskGenerator, err
 				if err != nil {
 					return common.WorkflowStepStatus{}, nil, errors.WithMessagef(err, "get input from [%s]", input.From)
 				}
-				if err := paramsValue.FillObject(inputValue, input.ParameterKey); err != nil {
+				if err := paramsValue.FillObject(inputValue, strings.Split(input.ParameterKey, ".")...); err != nil {
 					return common.WorkflowStepStatus{}, nil, err
 				}
 			}
diff --git a/pkg/workflow/tasks/custom/task_test.go b/pkg/workflow/tasks/custom/task_test.go
index d00dc5b7e..c3faddecc 100644
--- a/pkg/workflow/tasks/custom/task_test.go
+++ b/pkg/workflow/tasks/custom/task_test.go
@@ -48,7 +48,7 @@ myIP: value: "1.1.1.1"
 			return v.FillObject(ip)
 		},
 		"input": func(ctx wfContext.Context, v *value.Value, act types.Action) error {
-			val, err := v.LookupValue("prefixIP")
+			val, err := v.LookupValue("set", "prefixIP")
 			assert.NilError(t, err)
 			str, err := val.CueValue().String()
 			assert.NilError(t, err)
@@ -87,7 +87,7 @@ myIP: value: "1.1.1.1"
 			Type: "input",
 			Inputs: v1beta1.StepInputs{{
 				From:         "podIP",
-				ParameterKey: "prefixIP",
+				ParameterKey: "set.prefixIP",
 			}},
 		},
 		{