hi all: there are tow php files a.php and b.php, content of a.php as follows: <?php session_start(); if (!isset($_GET['flag'])) { header('Location: b.php'); } else { var_dump($_SESSION); } content of b.php as follows: <?php session_start(); session_commit(); $_SESSION['test'] = 'test'; session_commit(); header('Location: a.php?flag=1'); when i visit a.php, the dumped $_SESSION array is empty but if i commented the first session_commit() in b.php and then visit a.php, i cound see the $_SESSION array,which is not empty i wish i have descibed clear about my problem and someone could give me a feedback~ -- thanks, bugzhu