Abstract: Based on the Klingelnberg spiral bevel gear tooth surface processing principle, this paper established tooth surface equation.We used quasi-Newton method to establish the discrete tooth surface equations in MATLAB and then built the geometry model of Klingelnberg spiral bevel gear.Based upon the variable load contact finite element analysis theory, this paper researched three aspects.The first one was Klingelnberg spiral bevel gear meshing state in the variable load.The second one was the changes of contact path.The third one was required the relationship between the variable load and tooth contact path.According to the Klingelnberg spiral bevel gear high contact ratio and extracting three models of meshing tooth.We sought the contact trace changes in the light load, medium load, heavy load.The results shows that as the load increases the area of contact ellipse shape is gradully increasing and tilt direction, the location is subsequently changed.Contact path direction from horizontal direction gradually along the diagonal direction.According to the laws of the bearing contact area move.We can advance will contact area on the small side, so that to improve the bearing capacity of the gear.