Internal heat of bearing was calculated based on local heat source method. Convective heat transfer coefficient of bearing raceway was obtained considering different rotating speed under of oil air lubrication. Using the mixture multiphase flow model combined with the RNG k-ε turbulence model, and dynamic mesh method in Ansys Fluent software, twophase flow model of ball bearing was constructed. Temperature distribution of ball bearing was obtained by solve the model, the best oil quantity was given by analyzing the temperature distribution. Taking a ball bearing in high speed motorized spindle as an example, the temperature distribution of the bearing was calculated. The results show that the total friction bearing ratio increases sharply as the speed increases. There is the best oil quantity with a given operating condition, and the best oil quantity increases with the speed increases. Experiment results prove the reliability of the simulation model of oil air lubrication for ball bearing.