直接上代码： ~~~ - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. Method m1 = class_getInstanceMethod([self class], @selector(testExchange1)); Method m2 = class_getInstanceMethod([self class], @selector(testExchange2)); IMP impM1 = method_getImplementation(m1); IMP impM2 = method_getImplementation(m2); [self testExchange1]; [self testExchange2]; method_setImplementation(m2, impM1); method_setImplementation(m1, impM2); [self testExchange1]; [self testExchange2]; } - (void) testExchange1 { NSLog(@"%s", __func__); } - (void) testExchange2 { NSLog(@"%s", __func__); } ~~~ 输出： ~~~ 2015-11-02 13:54:12.646 02-runtime[2592:71972] -[ViewController testExchange1] 2015-11-02 13:54:12.647 02-runtime[2592:71972] -[ViewController testExchange2] 2015-11-02 13:54:12.648 02-runtime[2592:71972] -[ViewController testExchange2] 2015-11-02 13:54:12.649 02-runtime[2592:71972] -[ViewController testExchange1] ~~~ 另外还可以用method_exchangeImplementations  运行时交换两个方法的实现，[原文链接请点击](http://blog.csdn.net/lvdezhou/article/details/49585439)