In order to improve the wear resistance of titanium alloy,the plasma chromizing treatment of the duplex TC4 sample was carried out by vacuum glow plasma surface alloying technology. The local hardness and modulus of the sample were tested by nanoindentation. The fatigue properties of the specimens were evaluated by a rotary bending fatigue machine under a given load. The results show that the chromium alloy layer obtained after 5 hours of 850 ℃ treatment is composed of four sublayers,namely the Cr deposit layer,TiCr,2, layer,Ti,4,Cr layer and Cr-Ti solid solution layer. The elastic modulus and hardness of the adjacent sub-layers are significantly different,while the plasma chromizing treatment deteriorates the fatigue properties of the TC4 titanium alloy,and the fatigue life of the plasma chrome-plated sample can be increased by shot peening,which is attributed to The sample has the highest residual compressive stress,significant work hardening and a good balance of hardness and toughness.