Abstract: Water ring vacuum pumps are used in most of the mine gas extraction, and the temperature rise of pump shaft will not only shorten the life of the bearing itself, and lead to a sharp rise in the temperature of pump body, pump body with high temperature can cause the pump cavity internal corrosion, scaling and electrochemical corrosion problems, and it is a serious threat to extraction pump life and safe and efficient operation. Extraction pump shaft temperature changes are greatly influenced by quality of grease and fat injection rate, the current coal mine using extraction pump bearing mostly adopts the conical roller bearing, according to the actual circumstance of the macro rock mine gas extraction pumping station, calculate 2BEC water ring type vacuum pump uses the required cycle time and amount of theory on the conical roller bearing, combined with vacuum pump manufacturer given grease injection rate of the reference value, the scene with different fat injection rate to the observation records shaft temperature change, and the optimal lipid injection of the bearing is determined at a certain speed of gas extraction pump, which provides a powerful reference for the operation and maintenance of gas extraction pump station in coal mine.