针对LR-PON(长距离无源光网络)中ONU(光网络单元)的上行带宽分配问题,提出DBAPCP(基于流水周期轮询的动态带宽分配)算法;并使用OPNET软件对DBAPCP算法、IPACT(周期自适应交叉轮询)算法以及DBACP(基于周期轮询的动态带宽分配)算法进行建模仿真.由仿真结果可得:相比DBACP算法,DBAPCP算法提高了时延性能;相比IPACT算法,DBAPCP算法在高负载下,能够获得更低延时,并且能够更好地对区分等级业务进行支持. Aiming at the upstream bandwidth allocation of ONU (Long-haul Passive Optical Network) in LR-PON (Long-distance Passive Optical Network), this paper proposes a DBAPCP algorithm based on dynamic periodic polling of the water cycle and uses OPNET software to analyze the DBAPCP algorithm, Periodic adaptive cross-polling) algorithm and DBACP (periodic polling-based dynamic bandwidth allocation) algorithm.The simulation results show that compared with the DBACP algorithm, the DBAPCP algorithm improves the delay performance. Compared with the IPACT algorithm, DBAPCP algorithm can achieve lower latency under high load, and can better support differentiated level services.