for (NSString * familyName in [UIFont familyNames]) {

//字体家族名

//---Source Han Sans CN---

        NSLog(@"---%@---" , familyName);

        for (NSString *fontName in [UIFont fontNamesForFamilyName:familyName]) {

//字体名

//SourceHanSansCN-ExtraLight

 //SourceHanSansCN-Bold

//SourceHanSansCN-Medium

//SourceHanSansCN-Regular

//SourceHanSansCN-Light

            NSLog(@"%@" , fontName);

        }

    //例如：

    }

    NSArray * arr = @[@"SourceHanSansCN-ExtraLight",@"SourceHanSansCN-Bold",@"SourceHanSansCN-Medium",@"SourceHanSansCN-Regular",@"SourceHanSansCN-Light"];

    for (int i = 0; i<5; i++) {

        UILabel * label = [[UILabel alloc]initWithFrame:CGRectMake(0, 80*(i+1), self.view.bounds.size.width, 80)];

        label.numberOfLines = 0;

        label.font = [UIFont fontWithName:arr[i] size:20];

        label.text = @"summer 你好厉害啊";

        [self.view addSubview:label];

    }

iOS 系统字体 ：http://iosfonts.com/

自定义字体