Femtosecond laser finishing can be used as the final step in the precision machining of face gears. In this paper, the mechanism of the physical process action of the femtosecond laser ablation of the face gear material 18Cr2Ni4WA is studied. Based on the basic double temperature equation, the effect of electron density of states change is investigated, the dynamic energy heat transfer model of the femtosecond laser ablation of the face gear material is established, and the changes of electron temperature and lattice temperature of the femtosecond laser ablation of the face gear material are simulated and analysed. The experiments of femtosecond laser ablated gear material are carried out, and it is found that with the increase of energy density, the radius and depth of the crater are increased, the melt of the crater tends to increase, and there is a better quality of ablation when the energy density is 1.58 J/cm2. With the increase of pulse width, the morphological changes are not significant, but the melt production tends to decrease, and the crater tends to be flat. By studying the ablation law of the femtosecond laser ablation face gear material 18Cr2Ni4WA, it provides a reference for improving the precision machining quality of the face gear.