The failure of slope is a progressive process which from quantitative changes to qualitative changes. The whole sliding surface will be taken place by gradual damage of the potential sliding surface in the slope body gradually. Based on the strength reduction method

dynamic strength reduction method that can simulate the progressive failure of slope was proposed. At first

yielding approach index(YAI) is used to appraise the damaged region of slope in the numerical simulation

the region that YAI is less than 0.2 is recognized as the damaged region. Then through the continuous local damage reduction of the strength parameters of the local slope body

the potential sliding surface is damaged gradually and evolved to breakthrough finally. The practical results show that the proposed method can settle the reduction region in the strength reduction method effectively; and overcome the defect of large plastic damage area by the whole strength reduction method. The trend of displacement and damage area change also has better consistency in the reduction process. Dynamic strength reduction method can simulate the progressive failure of the slope truly; and it provides quantitative basis of slope stability appraising for strength reduction method.