Abstract: Centimeter precision satellite orbit is a prerequisite for completing the science, commercial and other tasks undertaken by LEO satellites, in which post-fit orbit accuracy assessment is one important part of the task. According to observation conditions and carried equipments, selectingappropriate accuracy assessment methods is helpful to evaluate the orbit determination result objectively and accurately. This paper takes GRACE for example, discusses the accuracy of internal and external assessment methods, and gets useful conclusions for the follow-up to China's domestic satellite precision orbit mission.