Abstract: To apply the surface physical vapor deposition(PVD) coating to power transmit gears under high-speed and heavy-load,a finite element analysis on load capacity of heavy-load transmit gear coating was carried out to investigate the influence of coating type,coating thickness and load level. Considering the complicated condition and actual load,using nonlinear spring element to simulate the interface,a gear coating contact mechanical calculation model was established. Based on experimental researches that other scholars have conducted,the results show that the main reason for coating crack is the equivalent stress of coating surface,and the coating thickness has a great influence on stress distribution. The main reason for coating peeling is the shear-stress of coating/base interface,and the coating thickness obviously influences the shear stress distribution. The load level affects the coating stress distribution and failure mode.