直接上代码：

关键代码：

NSMutableAttributedString * attributedString = [[NSMutableAttributedString alloc] initWithString:lab.text];

    NSMutableParagraphStyle * paragraphStyle = [[NSMutableParagraphStyle alloc] init];

    [paragraphStylesetLineSpacing:8];

 [attributedStringaddAttribute:NSParagraphStyleAttributeNamevalue:paragraphStylerange:NSMakeRange(0, [lab.textlength])];

    [labsetAttributedText:attributedString];