Tow kinds of Mo-N alloyed Iayers were fabricated on the surface of Ti6Al4V alloy by Xu-Tec process. One process was Mo-diffusing with nitriding simultaneously,and the other is nitriding after Mo-diffusing. This paper investigated their friction and wear behaviors against a polished 2100 steel counterbody ball under ball-on-disc test condition.It has been found that both the two Mo-N diffusion layers have excellent wear-resistant hehavior in sliding hut their friction coefficient increases slightly.The war rate for Mo-diffusing with simullaneous nitriding 400 times less than Ti6Al4V and 1080 times less for nitriding after Mo-diffusing.