方法如下：

function getMonthNum($date1, $date2, $tags = '-') {
      $date1 = explode($tags, $date1);     $date2 = explode($tags, $date2);     $year  = $date1[0] - $date2[0];     $month = $date1[1] - $date2[1];     if ($year > 0) {
          if ($month < 0) {
              return abs($year) * 12 - abs($month);         }         return abs($year) * 12 + abs($month);     } elseif ($year < 0) {
          if ($month > 0) {
              return abs($year) * 12 - abs($month);         }         return abs($year) * 12 + abs($month);     } else {
          if ($month > 0) {
              return $month;         }         return abs($month);     } }

$_monthCount = getMonthNum('2016-1', '2017-6'); 如有问题请留言给我哦，谢谢！