A numerical prediction on wear life formation is carried out in involute spur gear. The sliding velocity and contact pressures are computed along the contact zones at each rotational gear position, then the Continuous wear process are discretized by introducing wear step. A quasi-static model instead of the nonlinear wear model in the wear step is used to simulate the gear wear problem based on a generalized Achard wear equation which takes full account of the load and speed combined effects. A gear wear life prediction model is established, and then the procedures are developed which can predict the wear life of different gears or under different operating conditions.