Abstract: Based on a review in geometric modes in extensional tectonics, the basic deformation structure models are discussed. In the light of study on the geometric models of hanging-wall, several mathematical approaches are presented to balance deformed structure. The square matrix method is applied in simulation of rigid-body rotation and shift. The algebra equations of two structura1 restoration methods are employed in restoration of rollover above listric normal fault. These expressions provide basis for deriving computer algorithms In this way, the particles of deformed layers in the cross section can be restored to their original positions. It is also feasible in simulation of layer deformation. A computer program was designed for structure analysis, and has been applied in the oil field in the Huaifu Depression, Noah Jiangsu Basin, East China Basic structure features of this basin was illustrated after the interpreted seismic profile of line Fs1420 was restored, and the tepo-tectonics history of sedimentary was also revealed From the restored cross sections of line Fs1420, it can be seen that fault F0 was apparently the main fault, and controlled the development of Huaifu Depression, North Jiangsu Basin. Fault F2, fault F3 and fault F6 actived in the same extensional tectonic regime with the main fault occurred from the beginning of the first stage of Pukou Formation (K2p1 )in Late Cretaceous to the Cenozoic Since the reflected surface in seismic section TgO as the based the Pukou Formation(K2P) can not be identified clearly, the characteristics of fault F1 was difficult to define. After detailed study, it is infered that it is emplaced in forth stage of Pukou Formation(K2p4). The synthetic fault F4 and the antithetic fault F5 were controlled by fault F3 and were emplaced in Cenozoic Fault F7, a later antithetic fault, was also emplaced in Cenozoic The total extention of Huaifu Depression was 6280 m since 97Ma and the individual episode extention values and the extentional rate are calculated respectively (see Table 1) From K2P to K2p4, the extentional rate increased from 0.133 m per Ka to 0.733 m per Ka. Then during the Cenozoic the extentional rate decreased to 0.024 m per Ka. Therefore, two different stage of extensional activities of Huaifu depression were presented. For the early stag e in Late Cretaceous the tectonic extension is strongly active and for the later stage during the Cenozoic that is relatively weak and slow.