Abstract: To solve the problem of complex sources of crude oil in Kongqueting area, Xihu Sag, using geochemical analysis methods, oil samples from different structural locations of Kongqueting area were analyzed based on the characteristics of biomarker characteristics and carbon isotope. Oil sources were further analyzed. The characteristics of crude oil in different structural zones in Kongqueting area vary significantly. The first type of crude oil is mainly contributed by terrestrial higher plants, which mainly comes from local lipid-mirror hydrogen depleted coal measures source rocks, and crude oil of the high, middle, and low zones, as well as the crude oil of the southern wing, belongs to this type. The second type of crude oil with the dual contributions of terrestrial higher plants and aquatic organisms, and the crude oil of the northern wing belongs to this category, which mainly comes from the dark mudstone with hydrogen-rich lipid mirror in the surrounding deep layer. Based on the analysis of oil sources, this paper further clarifies the deep exploration potential of Xihu Sag.