The heat generated in the grinding zone plays an important role in the phase transformation that would alter the residual stress formation and surface integrity of work materials. Heat flux model is one of the key factors in calculating the heat into work piece. A new heat flux model based on the grinding actions is developed to calculate the grinding heat. The heat nux profile in the new heat flux model is very important and is discussed in detail. The finite element method is used to simulate the temperature fields. The comparison between simulation results and experimental results indicates the reliability of the proposed model. The simulation result from triangle heat flux model provides agreement with the experimental result in large cutting depth, and the simulation result from new heat flux model provides agreement with the experimental result in small cutting depth. Heat flux models should be selected to simulate temperature fields in various grinding conditions. It is helpful to study on grind-hardening technology and forecast and prevention of surface burn.