Abstract: The aim of this study is to introduce the concept of progressive failure into the stablity analysis of slope. The peak strength and residual strength of rock and soil masses are reasonably consided to be different in its role in the stability analysis. The comparative study with other methods of analysis and practical examples show the proposed computational model can be used for preliminary evaluation of slope stdbility and estimation of scope of failure and instability. This study also shows the important role of water in the slope stability.