To shorten the process of face gears, the grinding-hardening effect experiment of face gears under minimum quantity lubrication(MQL) was carried out. Firstly, the grinding method of face gears was analyzed based on the envelope principle, and the control equation of grinding move-ment was constructed. Secondly, the distribution ratio equation of heat flux density was estab-lished, and the theoretical calculation formula of triangle heat source was derived. Thirdly, since a MATLAB calculation program was compiled, the temperature change law under MQL grinding was analyzed. In the end, the influence of grinding parameters on the grinding-hardening layer depth was analyzed. The results demonstrate that MQL grinding achieves the grinding-hardening effect.