Abstract: PL20-2 oil field is located in the Miaoxinan uplift of the eastern Bohai sea area, located in the brink sags, the overall degree of exploration is low. By using reservoir geochemical methods, starting with the data of crude oil physical analysis and biomarker compounds, the geochemical characteristics of crude oil and the relationship between oil sources in Penglai 20-2 oilfield are analyzed in detail. The results show that the crude oil in this area is generated by the source rocks of Shahejie formation, and there are mainly three different directions. The crude oil in the main block A mainly comes from Bodong sag in the northwest direction. The characteristics of crude oil in eastern area B are similar to those in Penglai 15-2 Oilfield in Miaoxibei sag in the northwest direction and it is speculated that the crude oil mainly comes from Miaowenwa in the northwest direction. The oil sands extracted from the southern C area are similar to the characteristics of the Miaoxinan sag in the southwest direction and it is speculated that the crude oil mainly comes from Miaoxinan sag.