回答在Swift 3，

struct DeviceInformation {
    // UIDevice.current.model's value is "iPhone" or "iPad"，which does not include details; the following "model" is detailed, such as, iPhone7,1 is actually iPhone 6 plus
    static let model: String = {
        var size = 0
        sysctlbyname("hw.machine", nil, &size, nil, 0)
        var machine = [CChar](repeating: 0,  count: Int(size))
        sysctlbyname("hw.machine", &machine, &size, nil, 0)
        return String(cString: machine)
    }()

    static let uuid = UIDevice.current.identifierForVendor?.uuidString ?? ""
    static let idForAdService = ASIdentifierManager.shared().advertisingIdentifier.uuidString

    static func diviceTypeReadableName() -> String {
        switch model {
        case "iPhone1,1":   return "iPhone 1G"
        case "iPhone1,2":   return "iPhone 3G"
        case "iPhone2,1":   return "iPhone 3GS"
        case "iPhone3,1":   return "iPhone 4"
        case "iPhone3,3":   return "iPhone 4 (Verizon)"
        case "iPhone4,1":   return "iPhone 4S"
        case "iPhone5,1":   return "iPhone 5 (GSM)"
        case "iPhone5,2":   return "iPhone 5 (GSM+CDMA)"
        case "iPhone5,3":   return "iPhone 5c (GSM)"
        case "iPhone5,4":   return "iPhone 5c (GSM+CDMA)"
        case "iPhone6,1":   return "iPhone 5s (GSM)"
        case "iPhone6,2":   return "iPhone 5s (GSM+CDMA)"
        case "iPhone7,2":   return "iPhone 6"
        case "iPhone7,1":   return "iPhone 6 Plus"
        case "iPhone8,1":   return "iPhone 6s"
        case "iPhone8,2":   return "iPhone 6s Plus"
        case "iPhone8,4":   return "iPhone SE"
        case "iPhone9,1":   return "iPhone 7"
        case "iPhone9,3":   return "iPhone 7"
        case "iPhone9,2":   return "iPhone 7 Plus"
        case "iPhone9,4":   return "iPhone 7 Plus"
        case "iPod1,1":     return "iPod Touch 1G"
        case "iPod2,1":     return "iPod Touch 2G"
        case "iPod3,1":     return "iPod Touch 3G"
        case "iPod4,1":     return "iPod Touch 4G"
        case "iPod5,1":     return "iPod Touch 5G"
        case "iPod7,1":     return "iPod Touch 6G"
        case "iPad1,1":     return "iPad 1G"
        case "iPad2,1":     return "iPad 2 (Wi-Fi)"
        case "iPad2,2":     return "iPad 2 (GSM)"
        case "iPad2,3":     return "iPad 2 (CDMA)"
        case "iPad2,4":     return "iPad 2 (Wi-Fi)"
        case "iPad2,5":     return "iPad Mini (Wi-Fi)"
        case "iPad2,6":     return "iPad Mini (GSM)"
        case "iPad2,7":     return "iPad Mini (GSM+CDMA)"
        case "iPad3,1":     return "iPad 3 (Wi-Fi)"
        case "iPad3,2":     return "iPad 3 (GSM+CDMA)"
        case "iPad3,3":     return "iPad 3 (GSM)"
        case "iPad3,4":     return "iPad 4 (Wi-Fi)"
        case "iPad3,5":     return "iPad 4 (GSM)"
        case "iPad3,6":     return "iPad 4 (GSM+CDMA)"
        case "iPad4,1":     return "iPad Air (Wi-Fi)"
        case "iPad4,2":     return "iPad Air (Cellular)"
        case "iPad4,3":     return "iPad Air (China)"
        case "iPad4,4":     return "iPad Mini 2G (Wi-Fi)"
        case "iPad4,5":     return "iPad Mini 2G (Cellular)"
        case "iPad4,6":     return "iPad Mini 2G (China)"
        case "iPad4,7":     return "iPad Mini 3 (Wi-Fi)"
        case "iPad4,8":     return "iPad Mini 3 (Cellular)"
        case "iPad4,9":     return "iPad Mini 3 (China)"
        case "iPad5,1":     return "iPad Mini 4 (Wi-Fi)"
        case "iPad5,2":     return "iPad Mini 4 (Cellular)"
        case "iPad5,3":     return "iPad Air 2 (Wi-Fi)"
        case "iPad5,4":     return "iPad Air 2 (Cellular)"
        case "iPad6,3":     return "iPad Pro 9.7' (Wi-Fi)"
        case "iPad6,4":     return "iPad Pro 9.7' (Cellular)"
        case "iPad6,7":     return "iPad Pro 12.9' (Wi-Fi)"
        case "iPad6,8":     return "iPad Pro 12.9' (Cellular)"
        case "AppleTV2,1":  return "Apple TV 2G"
        case "AppleTV3,1":  return "Apple TV 3"
        case "AppleTV3,2":  return "Apple TV 3 (2013)"
        case "AppleTV5,3":  return "Apple TV 4"
        case "Watch1,1":    return "Apple Watch Series 1 (38mm, S1)"
        case "Watch1,2":    return "Apple Watch Series 1 (42mm, S1)"
        case "Watch2,6":    return "Apple Watch Series 1 (38mm, S1P)"
        case "Watch2,7":    return "Apple Watch Series 1 (42mm, S1P)"
        case "Watch2,3":    return "Apple Watch Series 2 (38mm, S2)"
        case "Watch2,4":    return "Apple Watch Series 2 (42mm, S2)"
        case "i386":        return "Simulator"
        case "x86_64":      return "Simulator"

        default:
            return ""
        }
    }
}

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");

                }
}

为了简单的比较，我总是喜欢宏观:

#define IS_IPOD [[UIDevice currentDevice].model containsString:@"iPod"]
#define IS_IPAD (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
#define IS_IPHONE (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)

它简单易用。

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.");
}

以下是新模型的小更新:

- (NSString *) platformString{
    NSString *platform = [self platform];
    if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 1G";
    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:@"iPod1,1"])   return @"iPod Touch 1G";
    if ([platform isEqualToString:@"iPod2,1"])   return @"iPod Touch 2G";
    if ([platform isEqualToString:@"iPod3,1"])   return @"iPod Touch 3G";
    if ([platform isEqualToString:@"i386"])   return @"iPhone Simulator";
    return platform;
}

你可以像这样使用UIDevice类:

NSString *deviceType = [UIDevice currentDevice].model;

if([deviceType isEqualToString:@"iPhone"])
    // it's an iPhone