According to its source, it is divided into four categories: animal oil, vegetable oil, petroleum lubricating oil and constituting lubricating oil.

The amount of petroleum lubricating oil accounts for more than 90% of the total consumption, so lubricating oil often refers to petroleum lubricating oil. It is mainly used to reduce the conflict between the appearance of moving parts, and has the effects of cooling, sealing, anti-corrosion, rust prevention, insulation, power transmission, cleaning impurities and other effects on machinery and equipment. Primarily, the lubricating oil fraction and the residue oil fraction from the distillation equipment are divided into materials. The primary function of a lubricating oil is viscosity, oxidation stability and lubricity, which are closely related to the composition of the lubricating oil fraction. Viscosity is an important quality index reflecting the fluidity of lubricating oils. Different operating conditions have different viscosity requirements. For heavy-duty and low-speed machines, high-viscosity lubricants should be used.

Oxidation stability shows the anti-oxidation ability of oil in the operating environment due to temperature, oxygen in the air, and metal catalytic effect. After the oil is oxidized, fine asphaltene-based carbon-like substances, such as viscous lacquer-like substances or paint films, or viscous water-containing substances, will be generated or reduced according to the operating conditions. Lubricity indicates the anti-wear function of lubricating oil. The concept of lubricating oil additives is to participate in one or more compounds in the lubricant in order to obtain some new characteristics of the lubricant or improve some of the characteristics already in the lubricant. According to their functions, the additives are mainly antioxidants and metal deactivators, extreme pressure antiwear agents, conflict modifiers (also called oily agents), detergents and dispersants, foaming agents, rust inhibitors, antioxidant preservatives, and pour point improvement. Agent, viscosity index improver, anti-emulsion and other types. The additives sold in the mall are generally the composites of the above single additives. What is different is the composition of the single additive and the share of several single additives in the composite additive.