This study presented a numerical model for the quantitative assessment of the heat transfer behavior of grinding media inside a ball mill. Effects of various mill speeds, grinding media filling, and the number of lifters on heat transfer were studied and verified by comparing the experimental results and the numerical simulations calculated by DEM (Discrete Element Method). The results show that the heat transfer of grinding media has a strong sensitivity to the variation of the mill speed, grinding media filling, and the number of lifters. The optimum grinding conditions for heat transfer behavior can be determined in terms of the temperature field of the grinding media. The maximum temperature rise of grinding media occurs at a range from 70% to 80% of critical speed. The maximum average temperature of grinding media up to 295.057 K appears at the grinding media filling 25% and the number of lifters 12. Subsequently, validation experiments are carried out to validate the numerical simulation results. The experimental results are closer to the simulation results, indicating the reasonability of the heat transfer model.