Abstract: In the coal mine under special conditions, high-speed power head sealing and temperature problems highlighted, constraining the performance and reliability of the coal mine rig. The main factors leading to the heat generation of the oil seal are theoretically analyzed. By comparing the temperature rise of the bearing, the box, the system and the sealing ring under the different rotational speed, three groups of laboratory test data are presented. The new sealing structure of the system oil circuit is discussed. The concrete measures to solve the problem of sealing and temperature rise are discussed, and verified in the industrial test.