Abstract: It is worthy of researching the force distribution and stability analysis during the progressive failure process of slope. The five sorts mechanical failure mechanisms are proposed for the thrust-type and tract-type landslide respectively, the another five sorts existence modes of the thrust-type slope status on site also suggested, the forward direction of slope failure is defined. The characteristics of progressive failure of slope can be described as: the failure mode of slope obeys the geo-material rule under the peak stress state, the critical stress state moves forward step by step under the condition that the slope failure occurs. The sliding force is greater than that of frictional resistance along the sliding face in the destruction zone. The bearing stress of geo-material reaches the maximum and its vector sum is equal to zero on the critical state. The frictional resistance is the same as the sliding force quantitatively in the stable and less-stable zones along sliding face, the pressure is equal to the reaction quantitatively in the entire sliding face. There exist force and moment balances under the critical state during the progressive failure process, when the shear and tensile failure occur by using the slice block method. The bearing stresses occur under the limit stress state, and the stress vector sum is equal to zero under the critical state for the tensile and shear failure. The rigid, flexible and rigid-flexible design methods are proposed for the protective measures of slope, and their location is also suggested. The failure ratio, failure percentage, failure area percentage, mechanical failure and engineering failure are defined respectively, and they can be used to evaluate the stability of slope. The force distribution rules of sliding face is analyzed during the progressive failure of slope. The conventional definition of stability factor which is equal to that of the frictional force is divided by sliding force along sliding face). The case studies indicate the main thrust method (or main traction method), comprehensive displacement method, surplus displacement method and tensile failure method are feasible to evaluate