let attributedString = NSAttributedString(string: "Title", attributes: [
    NSFontAttributeName : UIFont.systemFontOfSize(15), //your font here
    NSForegroundColorAttributeName : UIColor.redColor()
])

let alert = UIAlertController(title: "", message: "",  preferredStyle: .alert)

alert.setValue(attributedString, forKey: "attributedTitle")

let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (_) in
}

alert.addAction(cancelAction)

present(alert, animated: true, completion: nil)

在我的答案中添加了正确的代码行，因为它比下面的答案更加简洁。