Automobile air lubricating oil is used to lubricate the friction surface of compressor to conduct heat (cool and dissipate heat) and seal (prevent refrigerant leakage). As one of the key equipment of automobile, air compressor must be lubricated frequently to reduce friction and improve sealing performance, so air compressor must keep a certain amount of lubricating oil. Air compressor lubricating oil is usually called snow seed oil, which can circulate in the air compressor system together with refrigerant. Snow oil is a highly refined, foam-free, waxy and anhydrous lubricating oil. Air conditioning and lubricating oil have the lubricating, sealing and cleaning functions of general lubricating oil. Different from other lubricating oils, it has strong water absorption performance. Moisture is the enemy of air refrigeration system. If moisture is combined with refrigerant, hydrochloric acid will corrode parts and the expansion valve will be blocked by freezing. A small amount of snow seed oil and refrigerant will absorb water when circulating in the refrigeration system. Seed oil should be sealed during dehydration and normal use in the production process to prevent absorption of moisture in the air.