According to the thickening agent, it can be divided into two types: soap base and non-soap base. The thickening agent of the soap base is usually a metal soap such as lithium, sodium, calcium, aluminum or zinc, and a metal soap such as potassium, barium, lead or manganese. Non-soap base thickeners are graphite, carbon black, asbestos and synthetic (such as polyurea, bentonite). According to the application, they can be divided into general grease and special grease. The former is used for general mechanical parts. The latter is used in tractors, railway locomotives, marine machinery, oil drilling machinery, valves, etc. The main quality indicators are drop point, penetration, ash and moisture. The indicators used to evaluate the stability of the grease colloid are the oil separation test, the rolling bearing performance test, and the like. The roller test is a test method for testing the change in consistency under rolling. The fluidity test is a test method for evaluating the pumpability of grease at low temperatures. The water repellency test is a test method for evaluating the resistance of grease to water leaching. Colloidal stability is the property of the grease to maintain colloidal stability during storage and use, and liquid mineral oil does not precipitate out of the grease. Mechanical stability is a property that indicates the resistance of a grease to changes in consistency under mechanical operating conditions. The ball bearing torque test is a test method for evaluating the low temperature performance of grease. Grease is a stable solid or semi-solid product consisting of a thickener dispersed in a liquid lubricant, to which additives and fillers are intended to improve certain properties of the grease. Grease can be attached to vertical surfaces without loss at normal temperature, and can work in open or poorly sealed friction parts, with irreplaceable holding points of other lubricants. In general, the same soap base has better grease compatibility. The organoclay group is incompatible with other groups. Therefore, grease is used as a lubricating material in many parts of automobiles and construction machinery.