In order to explore the influence of low viscosity lubricating oil on turbocharged engine,three kinds of low viscosity test oil 0W20 and reference oil 5W30 were selected for bench tests,including engine mechanical loss test and engine universal characteristic test.Among them,different amounts of molybdenum friction modifier was added in the test oil 0W20-1 and 0W20-2,the fatty ester friction modifier was added in the test oil 0W20-3,and the test oil 0W20-1 had the lowest viscosity.The engine durability test was carried out by using the lowest viscosity test oil 0W20-1.The results show that under the two working conditions of full open and full close throttle,the friction torque of test oil 0W20-2 with high content of molybdenum friction modifier is the smallest.Compared with reference oil 5W30,the mechanical friction loss of engine can be reduced by 344% and 193% respectively.The mechanical loss is related to the type and amount of friction 〖JP+1〗modifier.Compared with fatty ester friction modifier,molybdenum containing friction modifier is more suitable for the condition of turbocharged engine and and has better effect of reducing friction work.Low viscosity oil can improve the fuel economy of vehicles,and the wear of key friction pairs of the engine is small,which can meet the requirements of engine durability.