Based on the method of the statistical probability, the theory forecasting model of grinding force is modified analytically. The calculated force is used as an input factor to calculate the heat flux. Then the transient grinding temperature field is simulated using the finite element analysis (FEA). An infrared imaging system for a full area temperature measurement is used to validate the numerical model. Additionally, the experimental results are synthesized with the simulation results to analyze the temperature field and the hardness penetration depth (HPD). The distribution of the temperature field and the stability of the grind-hardening process are discussed, which could provide a reliable forecasting method for optimizing the grind process and controlling the hardening effects forwardly.