Abstract:To verify the using feasibility of regenerated lubricating oil, a regeneration 15w40 lubricating oil for bus diesel engine generating from used 15w40 lubricating oil with membrane distillation was used as the research object, the decay of the physical and chemical indexes i.e. viscosity, acid value, alkali value, water content, insoluble matter and etc. were studied during the lubricating oil service period. The result showed that during the prescribed service period, along with the service time, the viscosity change rate, alkali value reduction ratio of base value, the water and insoluble matter content, as well as the Fe, Al, Cu and Si elements content were lower than the limit value from GB/T 7607—2010 which indicate when the oil should be changed except for the increase amount of acid value. The antioxidant capacity and contamination level of regenerative lubricating oil were relatively poor compare with that of original 15w40 lubricating oil. Therefore, we should pay particular attention to improve the antioxidant capacity and to reduce contamination level during the production of regenerative lubricating oil.