Abstract: In this paper, a new instrument analytical method for light crude is introduced, that is, the MS analytical method of hydrocarbon types. Hydrocarbon types data for eleven kinds of compounds including alkanes, cyclanes and aromatic hydrocarbons can be obtained rapidly by one sampling analysis. Using this method, the authors analysed 26 oil samples from several different regions in the Tarim Basin, Xingjiang.In order to take full use of the analytical results, a mathematical statistical method is employed to make calculation and analysis of all the results of MS analyses. As a consequence, three new geochemical parameters are suggested for the study of petroleum maturity, the types of oil-bearing mother material and the distance of oil and gas migration, At last, the three new parameters are applied by the authors to discussion on potential source rocks in the Tarim Basin.