Abstract: In order to analyze the progressive damage process of slope, the shear stress-strain intrinsic structure model was used to improve the traditional strip partition method by taking the residual thrust method as an example. The improved new strip partition method can analyze the progressive damage process of slope in theoretical calculation, and put forward the evaluation coefficient of landslide stability based on the critical state, and then judge the stability of sliding body in different stages of landslide according to the change of stability coefficient. Based on the engineering examples, the specific calculation process of the new strip partition method is discussed.