W, Mo, and W–Mo alloy films are prepared on 316L stainless steel by means of ion beam assisted deposition (IBAD). Tribological behaviors of the treated surfaces are investigated under lubrication with molybdenum dialkyldithiocarbamate (MoDTC) on a MS-T3000 friction and wear tester. The micromorphologies and chemical characteristics of the tribofilms generated on the worn surfaces are analyzed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. The results showed that the obvious synergistic effects of better friction reduction and wear resistance between W–Mo film and MoDTC are attributed to the hard surface and the high decomposition rate of additives on the worn W–Mo surface.