$week = date ( 'w' ) == 0 ? 7 : date ( 'w' );

$monday = strtotime ( 'today -' . ($week - 1) . 'day' );

$sunday = strtotime ( 'today +' . (8 - $week) . 'day -1second' );

$monday_date = date("Y-m-d", $monday);  // 本周一的日期（年-月-日）

$sunday_date = date("Y-m-d", $sunday);  // 本周日的日期（年-月-日）

echo "本周一：".$monday_date."<br>";

echo "本周日：".$sunday_date;