Abstract: Nanpu sag underwent multi?stage extensional subsidence and uplifting?erosion cycle evolution, formed six regional unconformities, which can be divided into two categories: parallel unconformity and truncation unconformity. The former includes the Carboniferous bottom and the Mesozoic bottom unconformities; the latter includes the Cenozoic bottom, the Shahejie formation member?1 bottom, the Dongying formation bottom and the Guantao formation bottom ones. The control effects of these unconformities on hydrocarbon accumulation in the study area are mainly manifested in the following three aspects: reservoir reconstruction, as the oil and gas migration channels and sealing. Vitrinite reflectance trend line method is used to recover the erosion thickness of Dongying formation in Gaoshangpu area, Combined with interval transit time method and stratigraphic correlation method, the erosion thickness of Dongying formation in other areas of Nanpu sag has been recovered. The study shows that the erosion intensity of Dongying formation in Nanpu sag could be divided into two districts: the strong erosion district in the northeast part and the week erosion district in the north?central part. Overall, the Dongying formation in Nanpu sag has suffered from erosion, its structural high is big, and its central sag area is small in denudation quantity