UILabel *reasonLabel = [[UILabel alloc] initWithFrame:CGRectMake(15, 15, UIScreenWidth - 30, textHeight)];
        reasonLabel.textColor = [UIColor colorWithHexString:@"#999999"];
        reasonLabel.numberOfLines = 0;
        reasonLabel.font = [UIFont systemFontOfSize:14];
        reasonLabel.adjustsFontSizeToFitWidth = YES;

//核心代码
NSMutableAttributedString * attributedString1 = [[NSMutableAttributedString alloc] initWithString:tempString];
            NSMutableParagraphStyle * paragraphStyle1 = [[NSMutableParagraphStyle alloc] init];
//间距为5
            [paragraphStyle1 setLineSpacing:5];
            [attributedString1 addAttribute:NSParagraphStyleAttributeName value:paragraphStyle1 range:NSMakeRange(0, [tempString length])];
            [reasonLabel setAttributedText:attributedString1];
            [reasonLabel sizeToFit];

[self.view addSubview:reasonLabel];