<?php
$input = "test:002005@1111@333333@;10205@2000@666666@;002005@1111@55555@;";
$input = rtrim($input,';');
$temp1 = explode(';',$input);
foreach($temp1 as $val1) {
        $temp2 = explode('@',$val1);
        $result[] = $temp2[2];
}
print_r($result);