- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
    if (scrollView == self.tableView)
    {
        CGFloat sectionHeaderHeight = 30; //区头高度
        if (scrollView.contentOffset.y <= sectionHeaderHeight&&scrollView.contentOffset.y >=0) {
            scrollView.contentInset = UIEdgeInsetsMake(- scrollView.contentOffset.y, 0, 0, 0);
        } else if (scrollView.contentOffset.y >= sectionHeaderHeight) {
            scrollView.contentInset = UIEdgeInsetsMake(-sectionHeaderHeight, 0, 0, 0);
        }
    }
}

这个方法存在一个弊端，就是当表视图存在导航条的时候，表视图会被导航条遮盖。所以需要添加如下代码

- (void)viewDidAppear:(BOOL)animated
{
    self.navigationController.navigationBar.translucent = NO;
}