In order to study the effect of water content on the additive consumption of unused oil without metal abrasive and used oil with metal abrasive,the oil samples of CD15W-40 diesel oil with water content from 0 to 0.8%(mass fraction) were prepared.The wear experiments of various lubricating oil samples were carried out by simulating the wear condition of the cylinder liner/piston ring friction pair of diesel engine.The FTIR analysis of lubricating oil samples after wear test was carried out to analyze the changes of additives content when the oil samples were stored in the environment without light for different times,and the results were compared with those of new lubricating oil samples before wear test.The results show that for unused oil,when the water content in the lubricating oil is 0.2% or more，the consumption speed of antifoam additive and detergent is increased with the increase of water content，while the consumption speed of antiwear additive has no direct relationship with the water content.For the used oil containing metal particles，the consumption rate of antifoam additive，antiwear additive and detergent is increased with the increase of water content when the water content in the lubricating oil is 0.1% or more.