In order to improve the reliability and durability of the aluminum piston of diesel engine,the microarc oxidation ceramic layer was prepared on the aluminum alloy matrix under different power duty cycle,and then the ceramic matrix selflubricating composite coating was prepared by introducing MoS2 nanoparticles into the pores of ceramic layer with electrophoretic technique.The influence of microarc oxidation power supply duty cycle on the microstructure of the composite coating,the thickness and surface roughness of the microarc oxidation ceramic layer and the ceramic matrix selflubricating composite coating was analyzed,and the tribological properties of the composite coating under dry friction and oil lubrication were studied on a reciprocating friction and wear tester.The results show that with the increase of duty cycle,the thickness and surface roughness of micro arc oxidation ceramic layer are first increased and then decreased.with the increase of duty cycle,the friction coefficient of ceramic matrix selflubricating composite coating is first decreased and then increased.The composite coating under duty cycle from 60% to 70% has the lowest friction coefficient,and the composite coating has a good bonding state with the substrate,which show remarkable antiwear and selflubricating effect.