Abstract: To explore the relationship between the hydrocarbon compositions of dewaxed oil and viscosity index and yield of base oil，the lube latent content and MS characterization of the narrow VGO fractions of four crude oils were analyzed. It is found that the yield and viscosity indexes of P+N components and related group hydrocarbon compositions as well as the yields of light and intermediate aromatic hydrocarbons can well be predicted by analyzing the group compositions of the dewaxed oil. The findings can replace tedious column separation process of lube latent content analysis method to increase the probability of high-quality crude oil screening.