In order to study the influence of the decline of physical and chemical performance parameters of lubricating oil on tribological properties, three performance indexes of lubricating oil, water content, viscosity and acid value were selected to study the change of wear resistance of lubricating oil at different contents. The effects of deterioration of different performance indexes on the tribological properties of lubricating oil were analyzed in detail by using the Rtec multifunctional tribology testing machine, and the surface of the sample under friction was characterized and analyzed by SEM scanning electron microscope and laser confocal microscopy. Result: The increase of water content of lubricating oil will lead to an increase in wear rate, and an appropriate decrease in friction coefficient. Lubricating oil with low viscosity has a low friction coefficient in the friction process, but the wear rate is high, and the lubrication advantage decreases when the viscosity of the lubricating oil decreases to a certain extent; In the absence of other undesirable substances, the increase of the acid value of the lubricating oil will reduce the friction coefficient, but the wear rate will continue to increase during the friction process, when the increase of the acid value exceeds 2mg· KOH/g, the wear rate increases dramatically.