在自定义cell里面

@property (nonatomic, strong) void ((^btnClick)());
- (void)btn:(UIButton *)sender{
   if (self.btnClick) {
       self.btnClick();
   }
}

 - (void)awakeFromNib {
      [_btn addTarget:self action:@selector(btn:)   forControlEvents:UIControlEventTouchUpInside];
}

在controller里面

#pragma mark ----- tabelView
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    FirstTableViewCell *cell = (FirstTableViewCell *)[tableView dequeueReusableCellWithIdentifier:@"FirstCellReuse"];
    if (cell == nil) {
        NSArray * nib = [[NSBundle mainBundle]loadNibNamed:@"FirstTableViewCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];
    }
    cell.nameLabel.text = self.array[indexPath.row];
    cell.btnClick = ^(){
        NSLog(@"%ld",(long)indexPath.row);
    };
    return cell;
}