$json = '{
"test":{
"1":{"id":4,"isim":"ahmet","kod":4147},
"2":{"id":32,"isim":"mehmet","kod":4528}
}
}';

$veriler = json_decode($json);

foreach( $veriler as $object ) {
foreach( $object as $v ) {
echo 'ID:'.$v->id . ' İsim:'.$v->isim . ' Kod:'.$v->kod. '
';
}
}
?>