//这个frame是初设的,没关系,后面还会重新设置其size。 UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0,0,0,0)]; label.numberOfLines = 0; label.backgroundColor = [UIColor clearColor]; NSDictionary *attributes = @{NSFontAttributeName:[UIFont systemFontOfSize:20],}; NSString *str = @"abcdefg你上课可是你的拿到了"; CGSize textSize = [str boundingRectWithSize:CGSizeMake(100, 100) options:NSStringDrawingTruncatesLastVisibleLine attributes:attributes context:nil].size;; [label setFrame:CGRectMake(100, 100, textSize.width, textSize.height)]; label.textColor = [UIColor greenColor]; label.text = str; [self.view addSubview:label];