Abstract: Spiral bevel gear milling tooth cutting force is an important basis for the design of bevel gear machine tools, and also an important basis for milling tooth vibration control, tool wear status monitoring, and cutting parameter optimization. According to the cutting process of forming spiral bevel gear wheels, this paper firstly derives the instantaneous chip area according to the principle of gear cutting and the geometric theory of spiral bevel gears. Then, using the material constitutive equation and the oblique angle cutting theory to calculate the stress in the shear zone of the material, the instantaneous cutting force model for machining the spiral bevel gear wheel by the forming method is constructed. Finally, a calculation program is written using Matlab software, and the theoretical cutting force model is tested and verified, which proves that the model has a certain accuracy.