Abstract: The Bohai Bay basin, Located in North China, is an active area for earthquakes, where 6 M≥7 earthquakes were recorded in history. Many studies on seismotectonic condition in the area have been reported. Based on the analysis to the tectonic feature in Paleogene and Neogene period in the area, and their relation with major earthquakes, the seismotectonic feature is studied. Since the effect of a NW-SE strike horizontal extension, an extensional fault system controlled by large detachment faults, such as the NE trending Taihang Mountain front fault, was formed in the upper crust at the early stage of the basin, and now a shear fracture system in the crust is developing due to a NEE-SWW trend compression. The extensional fault system may not be associated with earthquakes, but the shear faults system has close relation with the development and occurrence of earthquakes.