Abstract: The oxidizer CrO 3 was added into MoS 2 powder for changing the compositions of the oxides and sulfides formed on the metal surface in reciprocating motion. According to adhesive interfacial energy of frictional pairs, formation of oxides and sulfides, and energy theory, the lower friction coefficient and wear rate with MoS 2+CrO 3 lubricating were discussed as compared with MoS 2 lubricating.