diff --git a/src/class22/Animal.java b/src/class22/Animal.java
new file mode 100644
index 0000000..2fb675c
--- /dev/null
+++ b/src/class22/Animal.java
@@ -0,0 +1,8 @@
+package class22;
+
+public class Animal {
+
+    public void run(){
+        System.out.println("动物会跑~~~");
+    }
+}
diff --git a/src/class22/Test.java b/src/class22/Test.java
new file mode 100644
index 0000000..e440f7a
--- /dev/null
+++ b/src/class22/Test.java
@@ -0,0 +1,36 @@
+package class22;
+
+public class Test {
+    public static void main(String[] args) {
+        Animal a1 = new Tortoise();
+        a1.run();
+//        多态无法调用子类独有的方法
+//        a1.shrinkHead();
+        Tortoise t1 = (Tortoise)a1;
+        t1.shrinkHead();
+//        强制转换
+//        Wolf test1= (Wolf)a1;//运行时异常
+
+
+
+
+        System.out.println("=========================");
+
+        Wolf w = new Wolf();
+        go(w);
+        Tortoise t = new Tortoise();
+        go(t);
+    }
+
+    public static void go(Animal w){
+        System.out.println("开始......");
+        w.run();
+        if (w instanceof Tortoise) {
+            Tortoise t=(Tortoise)w;
+            t.shrinkHead();
+        } else if (w instanceof Wolf) {
+            Wolf w1=(Wolf)w;
+            w1.run();
+        }
+    }
+}
diff --git a/src/class22/Tortoise.java b/src/class22/Tortoise.java
new file mode 100644
index 0000000..2e062bc
--- /dev/null
+++ b/src/class22/Tortoise.java
@@ -0,0 +1,12 @@
+package class22;
+
+public class Tortoise extends Animal {
+    @Override
+    public void run() {
+
+        System.out.println("🐢跑的贼慢~~");
+    }
+    public void shrinkHead(){
+        System.out.println("🐢缩头了~~");
+    }
+}
diff --git a/src/class22/Wolf.java b/src/class22/Wolf.java
new file mode 100644
index 0000000..950022f
--- /dev/null
+++ b/src/class22/Wolf.java
@@ -0,0 +1,8 @@
+package class22;
+
+public class Wolf extends Animal {
+    @Override
+    public void run() {
+        System.out.println("狼跑的贼溜~");
+    }
+}