Abstract: To study the delamination process of a laminated shell, the 8-node isoparametric element formulation for laminated shells based on the Hamilton canonical equation in the Cylindrical Coordinates is derived firstly. Then the separating-combining model and the weak-interface model are used to simulate the delamination between layers. The solution for whole shells is obtained. For the perfect interface and delamination situation, the two models are analyzed and the energy release rate of the delaminated shell is obtained finally. The results of numerical examples show that the energy release rate of a circumferential delamination is larger than that of an axial delamination, and the laminated thickness affects greatly the two models.