A self-made adaptive compensator to compensating the first- and second-order PMD at same time is introuduced detailedly,in which DOP is used as signal for monitoring.The algorithm so-called Local neighborhood structure of Particle Swarm Optimization(LPSO) is firstly used in optimum searching and tracking process.The searching process is finished within one hundred milliseconds and the response time of tracking process is 16 milliseconds.The quasi-real time adaptive PMD compensation is realized.