Aiming at the problem that large modulus cycloidal bevel gear is difficult to be machined on dedicated gear milling machine,a method of constructing the tooth surface model of cycloidal bevel gear suitable for machining centers was proposed.Based on the processing principle of cycloidal bevel gear and the geometric relationship between the cutter head and the gear,a calculation method of gear processing parameters was established.The gear theoretical tooth surface was deduced according to the mathematical model of the gear cutting tooth processing,and the gear numerical tooth surface was obtained through the tooth surface discretization method.Based on the gear meshing mathematical model,the pinion tooth surface which was completely conjugated with the gear tooth surface was derived.By constructing a second-order modification difference surface in the normal direction of the fully conjugated pinion tooth surface and superimposing it,the pinion numerical tooth surface which was partially conjugated with the gear tooth surface was obtained.Finally,the loaded tooth contact analysis flow with finite element was established.Taking a pair of large modulus cycloidal bevel gear applied to the mine reducers as an example,the gear 3D modeling and loaded tooth contact simulation with finite element were conducted using ABAQUS software.The results show that under actual loading conditions,the pinion tooth surface constructed by conjugate modification is in local internal diagonal contact with the gear tooth surface,and the loaded contact area moves inside the gear tooth surface due to meshing dislocation,and it does not leave the tooth surface to produce edge contact,so the tooth contact area can meet the engineering need.The simulation results verify the feasibility of modeling method of conjugate tooth surface modification.