diff --git a/src/main/java/org/wlld/randomForest/Tree.java b/src/main/java/org/wlld/randomForest/Tree.java
index d0b1a62..c62da7f 100644
--- a/src/main/java/org/wlld/randomForest/Tree.java
+++ b/src/main/java/org/wlld/randomForest/Tree.java
@@ -12,7 +12,7 @@ import java.util.*;
 public class Tree {//决策树
     private DataTable dataTable;
     private Map<String, List<Integer>> table;//总样本
-    private Node rootNode;//根节点
+    private Node rootNode = new Node();//根节点
     private List<Integer> endList;//最终结果分类
 
     private class Node {
@@ -29,7 +29,7 @@ public class Tree {//决策树
         private double gainRatio;
     }
 
-    Tree(DataTable dataTable) throws Exception {
+    public Tree(DataTable dataTable) throws Exception {
         if (dataTable.getKey() != null && dataTable.getLength() > 0) {
             table = dataTable.getTable();
             this.dataTable = dataTable;
@@ -105,12 +105,11 @@ public class Tree {//决策树
                     Set<String> nowAttribute = removeAttribute(attributes, name);
                     Node sonNode = new Node();
                     nodeList.add(sonNode);
-                    sonNode.key = mapEntry.getKey();
                     sonNode.attribute = nowAttribute;
                     List<Integer> list = entry.getValue();
                     sonNode.fatherList = list;
                     int myNub = list.size();
-                    double ent = getEnt(list);//每一个信息熵都是一个子集
+                    double ent = getEnt(list);
                     double dNub = ArithUtil.div(myNub, fatherNub);
                     IV = ArithUtil.add(ArithUtil.mul(dNub, log2(dNub)), IV);
                     gain = getGain(ent, dNub, gain);
@@ -118,20 +117,28 @@ public class Tree {//决策树
                 Gain gain1 = new Gain();
                 gainMap.put(name, gain1);
                 gain1.gain = ArithUtil.sub(fatherEnt, gain);//信息增益
-                gain1.gainRatio = ArithUtil.div(gain1.gain, -IV);//增益率
+                if (IV != 0) {
+                    gain1.gainRatio = ArithUtil.div(gain1.gain, -IV);//增益率
+                } else {
+                    gain1.gainRatio = -1;
+                }
                 sigmaG = ArithUtil.add(gain1.gain, sigmaG);
                 i++;
             }
-            double avgGain = ArithUtil.div(sigmaG, i);
+            double avgGain = sigmaG / i;
             double gainRatio = 0;//最大增益率
             String key = null;//可选属性
             for (Map.Entry<String, Gain> entry : gainMap.entrySet()) {
                 Gain gain = entry.getValue();
-                if (gain.gain > avgGain && gain.gainRatio > gainRatio) {
+                if (gainRatio == -1) {
+                    break;
+                }
+                if (gain.gain >= avgGain && (gain.gainRatio >= gainRatio || gain.gainRatio == -1)) {
                     gainRatio = gain.gainRatio;
                     key = entry.getKey();
                 }
             }
+            node.key = key;
             List<Node> nodeList = nodeMap.get(key);
             for (int j = 0; j < nodeList.size(); j++) {
                 Node node1 = nodeList.get(j);
@@ -181,14 +188,16 @@ public class Tree {//决策树
     public void study() throws Exception {
         if (dataTable != null) {
             endList = dataTable.getTable().get(dataTable.getKey());
-            Node node = new Node();
-            node.attribute = dataTable.getKeyType();//当前可用属性
+            Set<String> set = dataTable.getKeyType();
+            set.remove(dataTable.getKey());
+            rootNode.attribute = set;//当前可用属性
             List<Integer> list = new ArrayList<>();
             for (int i = 0; i < endList.size(); i++) {
                 list.add(i);
             }
-            node.fatherList = list;//当前父级样本
-            createNode(node);
+            rootNode.fatherList = list;//当前父级样本
+            List<Node> nodeList = createNode(rootNode);
+            rootNode.nodeList = nodeList;
         } else {
             throw new Exception("dataTable is null");
         }
diff --git a/src/test/java/org/wlld/Food.java b/src/test/java/org/wlld/Food.java
index 78b817c..bdd0e4f 100644
--- a/src/test/java/org/wlld/Food.java
+++ b/src/test/java/org/wlld/Food.java
@@ -6,22 +6,31 @@ package org.wlld;
  * @date 8:11 上午 2020/2/18
  */
 public class Food {
-    private int foodId;
-    private double testId;
+    private int height;//身高
+    private int weight;//体重
+    private int sex;//性别 1男 2女
 
-    public int getFoodId() {
-        return foodId;
+    public int getHeight() {
+        return height;
     }
 
-    public void setFoodId(int foodId) {
-        this.foodId = foodId;
+    public void setHeight(int height) {
+        this.height = height;
     }
 
-    public double getTestId() {
-        return testId;
+    public int getWeight() {
+        return weight;
     }
 
-    public void setTestId(double testId) {
-        this.testId = testId;
+    public void setWeight(int weight) {
+        this.weight = weight;
+    }
+
+    public int getSex() {
+        return sex;
+    }
+
+    public void setSex(int sex) {
+        this.sex = sex;
     }
 }
diff --git a/src/test/java/org/wlld/MatrixTest.java b/src/test/java/org/wlld/MatrixTest.java
index 35a0aa9..8f6d113 100644
--- a/src/test/java/org/wlld/MatrixTest.java
+++ b/src/test/java/org/wlld/MatrixTest.java
@@ -2,7 +2,10 @@ package org.wlld;
 
 import org.wlld.MatrixTools.Matrix;
 import org.wlld.MatrixTools.MatrixOperation;
+import org.wlld.randomForest.DataTable;
+import org.wlld.randomForest.Tree;
 
+import java.awt.*;
 import java.util.*;
 
 /**
@@ -12,18 +15,31 @@ import java.util.*;
  */
 public class MatrixTest {
     public static void main(String[] args) throws Exception {
-        Map<Double, String> map = new TreeMap<>();
-        map.put(3.0, "a");
-        map.put(2.0, "b");
-        map.put(4.0, "c");
-        map.put(5.0, "d");
-        map.put(1.0, "e");
-        for (Map.Entry<Double, String> entry : map.entrySet()) {
-            System.out.println(entry.getKey());
-        }
+        test4();
+    }
 
+    public static void test4() throws Exception {
+        Set<String> column = new HashSet<>();
+        column.add("height");
+        column.add("weight");
+        column.add("sex");
+        DataTable dataTable = new DataTable(column);
+        dataTable.setKey("sex");
+        Random random = new Random();
+        for (int i = 0; i < 10; i++) {
+            Food food = new Food();
+            food.setHeight(random.nextInt(2));
+            food.setWeight(random.nextInt(2));
+            food.setSex(random.nextInt(2));
+            System.out.println("index==" + i + ",height==" + food.getHeight() +
+                    ",weight==" + food.getWeight() + ",sex==" + food.getSex());
+            dataTable.insert(food);
+        }
+        Tree tree = new Tree(dataTable);
+        tree.study();
     }
 
+
     public static void test3() throws Exception {
         Matrix matrix = new Matrix(4, 3);
         Matrix matrixY = new Matrix(4, 1);