我知道答案已经被勾选了，但为了将来的参考，你可以总是使用设备屏幕大小来找出它是哪台设备:

if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {

    CGSize result = [[UIScreen mainScreen] bounds].size;

    if (result.height == 480) {
        // 3.5 inch display - iPhone 4S and below
        NSLog(@"Device is an iPhone 4S or below");
    }

    else if (result.height == 568) {
        // 4 inch display - iPhone 5
        NSLog(@"Device is an iPhone 5/S/C");
    }

    else if (result.height == 667) {
        // 4.7 inch display - iPhone 6
        NSLog(@"Device is an iPhone 6");
    }

    else if (result.height == 736) {
        // 5.5 inch display - iPhone 6 Plus
        NSLog(@"Device is an iPhone 6 Plus");
    }
} 

else if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
       // iPad 9.7 or 7.9 inch display.
       NSLog(@"Device is an iPad.");
}

添加到Arash的代码，我不关心我的应用程序使用什么模型，我只想知道什么样的设备，所以，我可以测试如下:

    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
        {
            NSLog(@"I'm definitely an iPad");
    } else {
    NSString *deviceType = [UIDevice currentDevice].model;
                if([deviceType rangeOfString:@"iPhone"].location!=NSNotFound)
                {
                    NSLog(@"I must be an iPhone");

                } else {
                    NSLog(@"I think I'm an iPod");

                }
}

请随意使用这个类(gist @ github)

代码已删除并重新定位到 https://gist.github.com/1323251

更新(01/14/11)

显然，这段代码现在有点过时了，但它肯定可以使用Brian Robbins提供的这个线程上的代码进行更新，其中包括更新模型的类似代码。谢谢你在这个帖子上的支持。

我想添加一个私有API来检索设备的正面和外壳颜色:

UIDevice *device = [UIDevice currentDevice];
SEL selector = NSSelectorFromString([device.systemVersion hasPrefix:@"7"] ? @"_deviceInfoForKey:" :  @"deviceInfoForKey:");
if ([device respondsToSelector:selector]) {
    NSLog(@"DeviceColor: %@ DeviceEnclosureColor: %@", [device performSelector:selector withObject:@"DeviceColor"], [device performSelector:selector withObject:@"DeviceEnclosureColor"]);
}

我在博客上写过这方面的文章，并提供了一个示例应用程序:

http://www.futuretap.com/blog/device-colors/

这个代码怎么样，如果新版本发布，你将标识与最后知道的设备

- (NSString *)getModel {
    size_t size;
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);
    char *model = malloc(size);
    sysctlbyname("hw.machine", model, &size, NULL, 0);
    NSString *sDeviceModel = [NSString stringWithCString:model encoding:NSUTF8StringEncoding];
    free(model);                              
    if ([sDeviceModel isEqual:@"i386"])      return @"Simulator";  //iPhone Simulator
    if ([sDeviceModel isEqual:@"iPhone1,1"]) return @"iPhone1G";   //iPhone 1G
    if ([sDeviceModel isEqual:@"iPhone1,2"]) return @"iPhone3G";   //iPhone 3G
    if ([sDeviceModel isEqual:@"iPhone2,1"]) return @"iPhone3GS";  //iPhone 3GS
    if ([sDeviceModel isEqual:@"iPhone3,1"]) return @"iPhone3GS";  //iPhone 4 - AT&T
    if ([sDeviceModel isEqual:@"iPhone3,2"]) return @"iPhone3GS";  //iPhone 4 - Other carrier
    if ([sDeviceModel isEqual:@"iPhone3,3"]) return @"iPhone4";    //iPhone 4 - Other carrier
    if ([sDeviceModel isEqual:@"iPhone4,1"]) return @"iPhone4S";   //iPhone 4S
    if ([sDeviceModel isEqual:@"iPod1,1"])   return @"iPod1stGen"; //iPod Touch 1G
    if ([sDeviceModel isEqual:@"iPod2,1"])   return @"iPod2ndGen"; //iPod Touch 2G
    if ([sDeviceModel isEqual:@"iPod3,1"])   return @"iPod3rdGen"; //iPod Touch 3G
    if ([sDeviceModel isEqual:@"iPod4,1"])   return @"iPod4thGen"; //iPod Touch 4G
    if ([sDeviceModel isEqual:@"iPad1,1"])   return @"iPadWiFi";   //iPad Wifi
    if ([sDeviceModel isEqual:@"iPad1,2"])   return @"iPad3G";     //iPad 3G
    if ([sDeviceModel isEqual:@"iPad2,1"])   return @"iPad2";      //iPad 2 (WiFi)
    if ([sDeviceModel isEqual:@"iPad2,2"])   return @"iPad2";      //iPad 2 (GSM)
    if ([sDeviceModel isEqual:@"iPad2,3"])   return @"iPad2";      //iPad 2 (CDMA)

    NSString *aux = [[sDeviceModel componentsSeparatedByString:@","] objectAtIndex:0];

//If a newer version exist
    if ([aux rangeOfString:@"iPhone"].location!=NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPhone" withString:@""] intValue];
        if (version == 3) return @"iPhone4"
        if (version >= 4) return @"iPhone4s";

    }
    if ([aux rangeOfString:@"iPod"].location!=NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPod" withString:@""] intValue];
        if (version >=4) return @"iPod4thGen";
    }
    if ([aux rangeOfString:@"iPad"].location!=NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPad" withString:@""] intValue];
        if (version ==1) return @"iPad3G";
        if (version >=2) return @"iPad2";
    }
    //If none was found, send the original string
    return sDeviceModel;
}

我在我的应用程序中使用这个。截至2012年12月。

- (NSString *) platformString {
    // Gets a string with the device model
    size_t size;  
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);  
    char *machine = malloc(size);  
    sysctlbyname("hw.machine", machine, &size, NULL, 0);  
    NSString *platform = [NSString stringWithCString:machine encoding:NSUTF8StringEncoding];  
    free(machine); 

    if ([platform isEqualToString:@"iPhone1,1"])    return @"iPhone 2G";
    if ([platform isEqualToString:@"iPhone1,2"])    return @"iPhone 3G";
    if ([platform isEqualToString:@"iPhone2,1"])    return @"iPhone 3GS";
    if ([platform isEqualToString:@"iPhone3,1"])    return @"iPhone 4";
    if ([platform isEqualToString:@"iPhone3,2"])    return @"iPhone 4";
    if ([platform isEqualToString:@"iPhone3,3"])    return @"iPhone 4 (CDMA)";    
    if ([platform isEqualToString:@"iPhone4,1"])    return @"iPhone 4S";
    if ([platform isEqualToString:@"iPhone5,1"])    return @"iPhone 5";
    if ([platform isEqualToString:@"iPhone5,2"])    return @"iPhone 5 (GSM+CDMA)";

    if ([platform isEqualToString:@"iPod1,1"])      return @"iPod Touch (1 Gen)";
    if ([platform isEqualToString:@"iPod2,1"])      return @"iPod Touch (2 Gen)";
    if ([platform isEqualToString:@"iPod3,1"])      return @"iPod Touch (3 Gen)";
    if ([platform isEqualToString:@"iPod4,1"])      return @"iPod Touch (4 Gen)";
    if ([platform isEqualToString:@"iPod5,1"])      return @"iPod Touch (5 Gen)";

    if ([platform isEqualToString:@"iPad1,1"])      return @"iPad";
    if ([platform isEqualToString:@"iPad1,2"])      return @"iPad 3G";
    if ([platform isEqualToString:@"iPad2,1"])      return @"iPad 2 (WiFi)";
    if ([platform isEqualToString:@"iPad2,2"])      return @"iPad 2";
    if ([platform isEqualToString:@"iPad2,3"])      return @"iPad 2 (CDMA)";
    if ([platform isEqualToString:@"iPad2,4"])      return @"iPad 2";
    if ([platform isEqualToString:@"iPad2,5"])      return @"iPad Mini (WiFi)";
    if ([platform isEqualToString:@"iPad2,6"])      return @"iPad Mini";
    if ([platform isEqualToString:@"iPad2,7"])      return @"iPad Mini (GSM+CDMA)";
    if ([platform isEqualToString:@"iPad3,1"])      return @"iPad 3 (WiFi)";
    if ([platform isEqualToString:@"iPad3,2"])      return @"iPad 3 (GSM+CDMA)";
    if ([platform isEqualToString:@"iPad3,3"])      return @"iPad 3";
    if ([platform isEqualToString:@"iPad3,4"])      return @"iPad 4 (WiFi)";
    if ([platform isEqualToString:@"iPad3,5"])      return @"iPad 4";
    if ([platform isEqualToString:@"iPad3,6"])      return @"iPad 4 (GSM+CDMA)";

    if ([platform isEqualToString:@"i386"])         return @"Simulator";
    if ([platform isEqualToString:@"x86_64"])       return @"Simulator";

    return platform;
}