This paper proposes a slope stability analysis method considering progressive failure based on the limit equilibrium principle. The softening of soil is taken into account and the slip surface of arbitary shape is adopted.Formulation of the ploblem is carried out by using the slice method, and the analysis satisfies both force and moment equilibrium conditions. The basic idea of the proposed method is to define a local factor of safety at the base of each slice. Thus, the number of unknowns increases, and the ploblem becomes more highly undeterminate than those in the conventional slice methods. In order to render the ploblem determi-nate, two simplifying assumptions about the interslice forces and the line of thrust are simultaniously made which are separatly used in the Morgenstern-Price method and the Janbu method. An overall factor of safety is introduced to evaluate the whole stability of a slope. Finally, the results of an example problem show that the proposed analysis method can reasonably represent the actual behavior of the progressive failure of cl Slopes.