diff --git a/TNodeCore/Attribute/GraphUsageAttribute.cs b/TNodeCore/Attribute/GraphUsageAttribute.cs
index af08872..4eb9151 100644
--- a/TNodeCore/Attribute/GraphUsageAttribute.cs
+++ b/TNodeCore/Attribute/GraphUsageAttribute.cs
@@ -16,15 +16,14 @@ namespace TNodeCore.Attribute{
     public class GraphUsageAttribute:System.Attribute{
         public readonly Type GraphDataType;
         public string Category;
-        public GraphUsageAttribute(Type t,string category = null){
+        public GraphUsageAttribute(Type t,string category = "default"){
             //check if the type t is graph
             if(!typeof(GraphData).IsAssignableFrom(t)){
                 throw new Exception("The type used on Graph Usage must be a graph");
             }
             GraphDataType = t;
-            if (category != null){
-                Category = category;
-            }
+            Category = category;
+           
         }
     }
 
diff --git a/TNodeGraphViewImpl/Editor/Cache/NodeEditorExtensions.cs b/TNodeGraphViewImpl/Editor/Cache/NodeEditorExtensions.cs
index 5d55934..fcdcb48 100644
--- a/TNodeGraphViewImpl/Editor/Cache/NodeEditorExtensions.cs
+++ b/TNodeGraphViewImpl/Editor/Cache/NodeEditorExtensions.cs
@@ -18,8 +18,7 @@ namespace TNodeGraphViewImpl.Editor.Cache{
     /// Internal singleton class for caching TNode reflection Data.
     /// </summary>
     internal class NodeEditorTypeDictionary:Dictionary<Type, Type>{
-        private class NodeEditorTypeDictionaryComparer : IEqualityComparer<Type>
-        {
+        private class NodeEditorTypeDictionaryComparer : IEqualityComparer<Type>{
             public bool Equals(Type x, Type y){
                 return x?.ToString() == y?.ToString();
             }
@@ -28,11 +27,9 @@ namespace TNodeGraphViewImpl.Editor.Cache{
                 return obj.ToString().GetHashCode();
             }
         }
-
         public NodeEditorTypeDictionary():base(new NodeEditorTypeDictionaryComparer()){
             
         }
-
     }
     
     internal class NodeEditorSingleton{
@@ -132,6 +129,10 @@ namespace TNodeGraphViewImpl.Editor.Cache{
             var instance = (T)Activator.CreateInstance(implementedType);
             return instance;
         }
+        public static string GetTypeCategory(Type type){
+            var category = type.GetCustomAttribute<GraphUsageAttribute>();
+            return category?.Category ?? "";
+        }
         
         /// <summary>
         /// by given a generic type t,return the implementation instance  of the generic type
@@ -190,6 +191,13 @@ namespace TNodeGraphViewImpl.Editor.Cache{
             }
             return new List<Type>();
         }
+
+        public static List<string> GetGraphCategories(Type t){
+            var list = NodeEditorSingleton.Instance.GraphDataUsage[t];
+            //Merge same category
+            var res = list.Select(x=>x.GetCustomAttribute<GraphUsageAttribute>().Category).Distinct().ToList();
+            return res;
+        }
         public static BlackboardData GetAppropriateBlackboardData(Type t){
             if (NodeEditorSingleton.Instance.GraphBlackboard.ContainsKey(t)){
                 return (BlackboardData)Activator.CreateInstance(NodeEditorSingleton.Instance.GraphBlackboard[t]);
diff --git a/TNodeGraphViewImpl/Editor/NodeGraphView/DataGraphView.cs b/TNodeGraphViewImpl/Editor/NodeGraphView/DataGraphView.cs
index c5c515b..fcab94f 100644
--- a/TNodeGraphViewImpl/Editor/NodeGraphView/DataGraphView.cs
+++ b/TNodeGraphViewImpl/Editor/NodeGraphView/DataGraphView.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using TNode.Editor.Inspector;
 using TNode.Editor.Search;
 using TNodeCore.Editor.Blackboard;
@@ -12,6 +13,7 @@ using TNodeCore.Runtime;
 using TNodeGraphViewImpl.Editor.Cache;
 using TNodeGraphViewImpl.Editor.GraphBlackboard;
 using TNodeGraphViewImpl.Editor.NodeViews;
+using TNodeGraphViewImpl.Editor.Search;
 using UnityEditor;
 using UnityEditor.Experimental.GraphView;
 using UnityEngine;
@@ -397,10 +399,20 @@ namespace TNodeGraphViewImpl.Editor.NodeGraphView{
                 _data.blackboardData = NodeEditorExtensions.GetAppropriateBlackboardData(_data.GetType());
             }
         }
-
-
+        //TODO:Handling implicit conversion when two port types are different but compatible
+        private static bool HasImplicitConversion(Type baseType, Type targetType)
+        {
+            return baseType.GetMethods(BindingFlags.Public | BindingFlags.Static)
+                .Where(mi => mi.Name == "op_Implicit" && mi.ReturnType == targetType)
+                .Any(mi => {
+                    ParameterInfo pi = mi.GetParameters().FirstOrDefault();
+                    return pi != null && pi.ParameterType == baseType;
+                });
+        }
         public override List<Port> GetCompatiblePorts(Port startPort, NodeAdapter nodeAdapter){
-            return ports.Where(x => x.portType == startPort.portType || x.portType.IsAssignableFrom(startPort.portType)).ToList();
+            
+            return  ports.Where(x => startPort!=x &&  (x.portType == startPort.portType || x.portType.IsAssignableFrom(startPort.portType))).ToList();
+        
         }
 
         public virtual void OnGraphViewCreate(){
diff --git a/TNodeGraphViewImpl/Editor/Search/NodeSearchWindowProvider.cs b/TNodeGraphViewImpl/Editor/Search/NodeSearchWindowProvider.cs
index d7deafd..d2f2af7 100644
--- a/TNodeGraphViewImpl/Editor/Search/NodeSearchWindowProvider.cs
+++ b/TNodeGraphViewImpl/Editor/Search/NodeSearchWindowProvider.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using TNodeCore.Editor.NodeGraphView;
 using TNodeCore.Editor.Tools.NodeCreator;
 using TNodeCore.Models;
@@ -9,7 +10,7 @@ using UnityEditor.Experimental.GraphView;
 using UnityEngine;
 using UnityEngine.UIElements;
 
-namespace TNode.Editor.Search{
+namespace TNodeGraphViewImpl.Editor.Search{
     public class NodeSearchWindowProvider:ScriptableObject,ISearchWindowProvider{
         private Type _graphType;
         private GraphView _graphView;
@@ -21,20 +22,26 @@ namespace TNode.Editor.Search{
         }
         public List<SearchTreeEntry> CreateSearchTree(SearchWindowContext context){
             var nodeDataTypes = NodeEditorExtensions.GetGraphDataUsage(_graphType);
+            var categories = NodeEditorExtensions.GetGraphCategories(_graphType);
             
             var list = new List<SearchTreeEntry>{
-                new SearchTreeGroupEntry(new GUIContent("Add New Node"), 0),
+               
             };
-            //TODO a node icon shall be given by some way
+            var root = new SearchTreeGroupEntry(new GUIContent("Create"),0);
+            list.Add(root);
             Texture2D icon = new Texture2D(2,2);
-            foreach (var nodeDataType in nodeDataTypes){
-                Debug.Log(nodeDataType.Name);
-
-                
-                list.Add(new SearchTreeEntry(new GUIContent($" {nodeDataType.Name} ",icon)){
-                    level =  1,
-                    userData = nodeDataType,
+            foreach (var category in categories){
+                var categoryEntry = new SearchTreeGroupEntry(new GUIContent(category),1);
+                list.Add(categoryEntry);
+                nodeDataTypes.Where(x => NodeEditorExtensions.GetTypeCategory(x).Equals(category)).ToList().ForEach(x => {
+                    var nodeDataType = x;
+                    var nodeDataTypeEntry = new SearchTreeEntry(new GUIContent($" {nodeDataType.Name} ",icon)){
+                        level = 2,
+                        userData = nodeDataType
+                    };
+                    list.Add(nodeDataTypeEntry);
                 });
+
             }
             return list;
         }
@@ -55,8 +62,5 @@ namespace TNode.Editor.Search{
             }
             return false;
         }
-        
-        public NodeSearchWindowProvider(){
-        }
     }
 }
\ No newline at end of file