A reliability allocation method of satellite navigation system based on dynamic simulation is proposed in this paper.First,Bayesian network is used for allocating the service availability and continuity to a slot.Then,the dynamic colored Petri net is applied to modeling the navigation information flow,which describes the availability and reliability associating the slot with the satellite,control center,mission up-link station and sensor station.Meanwhile,Monte Carlo simulation method is used to determine the availability and reliability index of key functional units.Finally,under conditions of the allocation availability and reliability index,the service availability and continuity is got with the bottom-up approach.Results are consistent with the original allocated values,which verify the validity of the proposed method.