Oil seal is a sealing element used to seal the rotating shaft in mechanical equipment, and the cavity is basically a static metal framework, just like the steel bar in the concrete component, which plays a reinforcing role, and enables the oil seal to maintain the shape and tension, and at the same time prevents the fluid from leaking and invading from the contact surface between the outer surface of the oil seal and the inner surface of the cavity. At the same time, the high temperature resistance is better than that of NBR material. Under the condition of no lubrication, pure drying and multi-media, it is recommended to use PTFE sealing lip to make oil seal. Its sealing lip has enough lubrication capacity, greatly reducing the wear of lip. A single oil seal is not suitable to seal two different media. A large number of chemicals increase the impact on the material performance of the oil seal. The compatibility of the oil seal to the sealing media should be determined through laboratory tests. Oil seal is an important part widely used in industry. In order to promote the rapid development of oil seal industry, various countries have formulated a series of relevant standards.