Abstract: The Langgu subdepression is a majou oil-producing area in the North China oil field. On the basis of the hole core data combined with the seismic data and by using the basic principles of sequence stratigraphy and seismic stratigraphy, the authors studied the Paleogene in the subdepression, distinguished depositional sequences, revealed the tectonic framework of sequence stratigraphy and probed into the characteristics of the regional depositional framework and their controlling effects on petroleum generation and accumulation.