本文通过在上海大众、日本尼桑、二汽东风等车辆上,使用15w/40或SD级汽油机机油,经过长期的跟踪试验,定期从试验车辆上抽取油样,在实验室里进行油品理化性能、铁谱和光谱分析,评判油品质量的衰变规律,在对大量实验数据进行分析处理的基础上,利用统计分析的方法,确定润滑油的更换周期.结果表明,合理地确定换油周期,实行按质换油,才能保证科学地使用汽车发动机润滑油. In this paper, we used 15w / 40 or SD class gasoline engine oil on Shanghai Volkswagen, Nissan, Erqi and Dongfeng vehicles to carry out regular testing of oil samples from the test vehicle and physical and chemical properties of the oil in the laboratory through long-term follow-up tests , Iron spectrum and spectral analysis to judge the decay law of oil quality.On the basis of analyzing and processing a large number of experimental data, the method of statistical analysis was used to determine the replacement period of lubricating oil.The results show that, The implementation of oil by quality, in order to ensure the scientific use of car engine lubricants.