function timediff( $begin_time, $end_time )

{

  if ( $begin_time < $end_time ) {

    $starttime = $begin_time;

    $endtime = $end_time;

  } else {

    $starttime = $end_time;

    $endtime = $begin_time;

  }

  $timediff = $endtime - $starttime;

  $days = intval( $timediff / 86400 );

  $remain = $timediff % 86400;

  $hours = intval( $remain / 3600 );

  $remain = $remain % 3600;

  $mins = intval( $remain / 60 );

  $secs = $remain % 60;

  $res = array( "day" => $days, "hour" => $hours, "min" => $mins, "sec" => $secs );

  return $res;

}

//======== 实例使用 ========

$timediff = timediff( strtotime( "2011-10-28" ), strtotime( "2011-10-29" ) );

print_r( $timediff );

<?php

$one = strtotime('2011-12-08 07:02:40');//开始时间 时间戳

$tow = strtotime('2011-12-25 00:00:00');//结束时间 时间戳

$cle = $tow - $one; //得出时间戳差值

/* 这个只是提示

echo floor($cle/60); //得出一共多少分钟

echo floor($cle/3600); //得出一共多少小时

echo floor($cle/3600/24); //得出一共多少天

*/

/*Rming()函数，即舍去法取整*/

$d = floor($cle/3600/24);

$h = floor(($cle%(3600*24))/3600);  //%取余

$m = floor(($cle%(3600*24))%3600/60);

$s = floor(($cle%(3600*24))%60);

echo "两个时间相差 $d 天 $h 小时 $m 分 $s 秒"