Emergency power supply plays an important and irreplaceable role in the restoration of power supply after a disaster in a resilient distribution network. Mobile energy storage systems (MESSs) can be used as emergency power sources to restore power to important loads. Among them, how to configure MESS reasonably is of great significance in order to recover power supply of important load nodes quickly after disasters. This paper proposes an optimized configuration method of MESS in a resilient distribution network considering efficiency improvement. First of all, considering the risk of power outages of each node in the distribution network and the shortest time limit allowed for the area, the number and location of the most optimal site points in the area are given; secondly, according to the shortest moving distance and shortest moving time of MESS, the priority is established. The optimal configuration model of MESS with hierarchical load recovery, and the objective function minimize the comprehensive cost after the disaster are established. The model proposed in this paper realizes the priority restoration of power supply for important loads by dividing the importance levels of loads, which improves the utilization efficiency of MESS. Finally, a numerical example is used to verify the correctness and effectiveness of the proposed configuration model.