In the precision machining process of high precision RV reducer cycloid gear tooth surface,the grinding wheel is included in the tooth groove,and most of the grinding can be converted into thermal energy,causing the temperature of grinding zone to rise sharply. The high grinding temperature will cause secondary tempering burn,white layer and other thermal damage on the surface of the tooth surface. In order to control and prevent the occurrence of thermal damage,the temperature field distribution of tooth surface is simulated by using different grinding process parameters under wet grinding conditions. The heat distribution ratio and convection heat dissipation coefficient of the grinding process are calculated by using the theoretical analysis,and the temperature field distribution of the tooth surface under wet grinding is simulated by means of finite element method and computer simulation software. The results show that the depth of grinding（ ap） has a great influence on the distribution of temperature field. The convective heat transfer of coolant can effectively reduce the temperature of the tooth surface in time,and the finishing environment of cycloid gear tooth surface should be under wet grinding condition. When other grinding process parameters are unchanged,with the increase of grinding depth,the cooling effect of grinding fluid will slow the temperature rise gradient of the tooth surface. The simulation results are of great value in predicting the temperature distribution of the cycloidal gear tooth surface under wet grinding conditions and the reasonable selection of the parameters of wet grinding teeth.