Performance improvement is very much important for PON system especially in Gigabit Passive Optical Network (GPON). Real time traffic prediction can improve the performance of GPON system. H-DBA, a real time Dynamic Bandwidth Allocation is proposed for performance improvement for GPON System. Proposed H-DBA meets technical requirements of optical network for high bandwidth, low delay and low packet loss with respect to real time traffic prediction. Using high order moving traffic prediction model, H-DBA scheme predicts the amount of high priority traffic arriving during the waiting period, as a basis for bandwidth allocation, so as to ensure the performance of high priority services. Simulation results show that the H-DBA scheme proposed in this paper has good performances on ad-hoc based traffic prediction.