Baoding sag is located in the west of the Jizhong depression in the Bohai Bay Basin, separated with Taihang Mountains uplift by the Taihang Mountains piedmont fault. The dividing of tectono-stratigraphic sequences plays an important role in the determination of tectonic evolution stages and the exploration of petroleum resources in this area, and it can also provide significant clues to constrain the evolution of the Taihang Mountains piedmont fault. This paper documents the stratigraphic framework of the Baoding sag in using the latest seismic profiles, drilling data integrate with regional geological mapping results. The tectono-stratigraphic sequences are constrained by the regional unconformities, and the tectonic evolution of the study area is discussed based on the balanced section technique. Two regional unconformities including the bottom of the Paleogene Kongdian Formation and the bottom of the Neogene Guantao Formation are revealed, according to which three structural layers are recognized basement structural layer, rift structural layer, and depression structural layer. The tectonic evolution of the Baoding sag experienced basement formation period, Paleogene rift period, Late Oligocene inversion period, and Neogene-Quaternary depression period. The Paleogene rift period can be subdivided into three stages as well as strong rift stage, continuous rift stage and late rift stage.