Abstract: The early exploration in Baoding Sag in Bohai Bay Basin mainly targeted at the buried hill and deep Paleogene, but no substantial discovery was achieved in nearly 60 years. Based on 3D seismic acquisition and 2D seismic re-processing, the geological structure was reunderstood as a whole, and the following results were obtained: (1) In the Early-Middle Paleogene (during the deposition period of Kongdian Formation-Second member of Shahejie Formation), the fault rift activity was strong in the west and weak in the east, and the lake basin was shallow and small in sedimentary range; In the Late Paleogene (during the deposition period of the first member of Shahejie Formation-Dongying Formation), the fault rift activity was strong in the east and weak in the west, and it was a large lake basin in the maximum flooding period. (2) The organic-rich algal source rock in the saline lake basin in the lower part of the first member of Shahejie Formation experienced early and multi-stage hydrocarbon generation, forming early and low mature oil. (3) The reservoir-cap rock combination in shallow Dongying Formation is good, which is the main target layer. In addition, hydrocarbon accumulation pattern of “two-way hydrocarbon supply, hydrocarbon transport by sand and fault, and hydrocarbon enrichment in shallow formation” is constructed. As a result, several exploratory wells such as G77X and BQ1X were drilled in the optimally selected Qingyuan structural belt, and high-yield oil flows were tested in Dongying Formation,marking an exploration breakthrough in Baoding Sag, and confirming the oil and gas enrichment in shallow formation in the first row of sags in Taihang piedmont, which had reference significance for the exploration of mature oilfields in Bohai Bay Basin.