The effects of different profiles on skirt side force, contact pressure, engine knock kinetic energy and wear load were determined through the design and research of piston skirt profile of China Ⅵ diesel engine combining the FEA and piston dynamic analysis. The optimization result shows that the skirt wear load drops by about 47.3% by using the longitudinal profile of accumulative power function and the modified outer circular profile of varying ellipse skirt. By using the optimized skirt profile, the reduction of skirt wear is significant. The accuracy of simulation analysis and the advance of profile design were both verified after 1 000 h endurance test.