The Bohai Sea lies in the east of the Bohai Basin. It's a place where neo-tectonic activity is strong in North China. Faults are common in the sedimentary strata of the basin. Many researchers have studied the neo-tectonics of the Bohai Sea from different aspects,and get different conceptions. The authors have made a number of studies of the neo-tectonics of the Bohai Sea and confirmed the neo-tectonics in the Bohai Sea began from the later of Neogene(12~10Ma BP). We also studied the faults distribution from three-dimensional space,and divided the neo-tectonic faults into the continued active faults and the newly formed faults on the basis of the genetic relationship of basement faults. They could be divided into three major neo-tectonic activity fault zones,the Yingkou-Weifang fault zone of north-northeast with continuous activities and weakly active right lateral thrust movement,the Beijing-Penglai fault zone of northwest-west with continuous activities and strongly active left lateral positive movement,the Northwest Miao Island-the Yellow River Estuary Fault zone of northwest which is newly formed with strongly active right lateral translational movement,. The latter two formed a partially conjugated active tectonic zone,dominated by the Northwest Miao Island-the Yellow River Estuary Fault zone,and the seismic activity has close relationship whit it. Finally,the neo-tectonic stress field of northeast-east-southwest-west horizontal conpression,and its relationship with neo-tectonic active fault zones have been discussed. The neo-tectonic stress field is quite different from the rift stage of the Bohai basin in the Paleogene. The neo-tectonics is the crust conjugate shear rupture system. The Paleogene basin tectonics is extensional structure in the upper crust,which forms two different structural systems under different tectonic mechanism.