This paper summarizes the structural styles of extensional fault-related folding, which includes extensional fault-propagation fold and extensional fault-bend fold and etc. Extensional fault-propagation fold forms upon a steep fault. The normal fault propagated upward, bending the covering strata, which is similar with the model of tri-shear deformation. Chezhen depression is a typical Mesozoic-Cenozoic half-graben in the Bohai Bay Basin. Based on detailed structural geometric analysis of the seismic profiles across Chezhen depression and South slope zone of Chezhen depression, an obvious structural style of syncline is identified, which is not resulted from structure compression but from extensional fault-propagation folding. Using the theories of extensional fault-related fold and the tri-shear model, we modeled the kinematic process of extensional faults in Chenzhen depression. We present the geometric features of extensional fault-related folds and process of deformation in Chezhen depression, which deepens the comprehension to the structural styles of half-graben of Bohai Bay basin.