diff --git a/io.sc.engine.rule.core/src/main/java/io/sc/engine/rule/core/code/generator/impl/ParameterGenerator.java b/io.sc.engine.rule.core/src/main/java/io/sc/engine/rule/core/code/generator/impl/ParameterGenerator.java
index 4c718f5d..68b3d6a0 100644
--- a/io.sc.engine.rule.core/src/main/java/io/sc/engine/rule/core/code/generator/impl/ParameterGenerator.java
+++ b/io.sc.engine.rule.core/src/main/java/io/sc/engine/rule/core/code/generator/impl/ParameterGenerator.java
@@ -307,11 +307,12 @@ public class ParameterGenerator {
         for (Parameter parameter : parameters) {
             if(ParameterType.INDICATOR.equals(parameter.getType())){
                 IndicatorParameter indicatorParameter =(IndicatorParameter)parameter;
-                sb.append("this.").append(IdReplacer.fieldName(parameter.getCode()));
+                String fieldName =IdReplacer.fieldName(parameter.getCode());
+                sb.append("if(this.").append(fieldName).append("==null){ this.").append(fieldName);
                 sb.append(" =");
                 sb.append("libs.get(\"").append(IdReplacer.varName(indicatorParameter.getLibCode(),indicatorParameter.getLibVersion())).append("\")");
                 sb.append(".").append(IdReplacer.fieldName(indicatorParameter.getIndicatorCode()));
-                sb.append(";").append("\n");
+                sb.append("; }").append("\n");
             }
         }
         return sb.toString();