Abstract: The differential pulse voltammetry method was used for determination of antioxidant type, remaining content, and the remaining life of the lube oil. The 0.1 mol/L KOH 92% ethanol-water solution was selected as the extraction liquid after the contrast test. The experiments provide the pulse signals of three kinds of antioxidants: 2,6-ditertbutylmethylphenol, the N-phenyl-a-naphthylamine, and zinc dialkyl dithiophosphate (ZDDP) for usage of qualitative analysis. The antioxidant decay curves of CF-4 and hydraulic 10 lubricants with aging time were obtained by simulated aging test. Thus the lube oil remaining residual life can be predicted based on the remaining content of antioxidant. The results show that the measurement method can be used not only for qualitative analysis of kinds of antioxidant in lubricating oils, but also for effective evaluation of the lubricating oil life and working state.