Abstract: The support legs are the positioning and support functional components of the Reactor pressure vessel inspection equipment (EPR CIME). The rationality of the structure has important influence on the positioning accuracy and reliability of EPR CIME. According to EPR nuclear reactor pressure vessel structure of the third generation nuclear power plants, the support legs were designed with the function of automatic centering, and the reliability of the support legs was analyzed by using ANSYS method, then a mechanics experiment was carried out. Mechanics experiment verified the theoretical analysis results, and proved that the design of support legs were reasonable and feasible.