According to the structure of the high speed electric spindle, the main heat transfer mecha—nism and the rate calculation method of heat source production.the calculation parameters were put into ANSYS finite element analysis software and the element analysis model was established in order to get electric spindle temperature field information.The influence of bearing preloaded forces, the no—tor speed, bearing cooling air flow rate on electric spindle hot modal were analyzed.The results show that the size of the preloaded force has little influence on the temperature rise of bearing；Motor speed and cooling air flow have apparent influence on the temperature rise of bearing.According to the re. suits, this paper puts forward improving electric spindle heat response measures.