Low temperature has a significant effect on the oil lubricating performance because of viscosity becoming larger,and fluidity and additive activity getting worse.PAO base oils with different viscosity were selected as the research object,the rheology,wear,and lubrication properties of the PAO base oils and the oil samples with extreme pressure anti-wear additive at low temperature were studied using MCR302 rheometer and SRV tribo-tester.Testing results show that the viscosity of PAO oils increases significantly as the temperature decreases.The higher the viscosity of the oil sample,the more obvious the influence of low temperature.PAO oils show obvious shear thinning phenomenon at low temperature.Low temperature reduces the activity of extreme pressure anti-wear additive,and the additive has no improvement in the performances of friction reduction and anti-wear of the oil samples.Therefore,low temperature plays an obvious effect on the tribological performances of PAO base oils and additives,and hinders the friction reduction and anti-wear functions of base oils and additives.