Abstract: Based on the study of the chromatogram of terpane m/e 191 fragment,the 5 types of crude oil from the Beijing and Tianjin region are divided into two groups:one with abundant terpane and the other with only a small amount of terpane.It is believed that the oil in the third member of Shahejie Formation(Es₃)comes primarily from the Es₃ source rock,and the crude oil in the fourth member of Shahejie(Es₄)-Kongdian Formation and the buried hill comes from Es₄-Kongdian source rock.By using the parameters of sterane isomers,4 sources are determined for the crude oil of the region,among whicn 4 are of a single origin and 1 of mixed origin.