Abstract: Four kinds of nanocrystalline (Mo1-xCrx)Si2(x=0, 0.09, 0.18, 0.27) coatings were prepared on TC4 alloy surface by a double cathode plasma sputtering technique, and the microstructure, binding force with the substrate and friction and wear properties of the coatings were investigated. The results show that the coatings exhibited homogeneous and dense microstructure and good binding force with the substrate. The harness and elastic modulus of the coatings were all increased with increasing Cr addition, but the friction coefficient and wear rate all reduced.