Abstract: The Bohai bay Basin is a Cenozoic rifting one.Based on a synthetic study of the litho-spheric structure and basinal tectonic characteristics of the basinal area,the extensional deformation of the continental lithosphere can be interpreted as a double or muliple layered extensional pattern, which is dominated by simple shear extensional deformation in the upper part and pure shear extensional deformation in the lower part. Thermal action withinthe mantle is a major factor which controls thc dynamic process of rifting extension in thebasinal area, as shown by the "event" sequences of the tectonic evolution proces,in thebasinal area. Nevertheless, the strike-slip of the deep fault is driven by regional stressfield formed by plate boundary effort transferring to the basinal area.