出现这个问题是设置约束优先级错误，设置一下约束的优先级就行。
[self.doctorTitle mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.equalTo(self.title.mas_left);
make.right.equalTo(self.title.mas_right);
make.top.equalTo(self.topline.mas_bottom).offset(10).priorityHigh();
make.height.mas_equalTo(@14);
}];