Abstract: An unified approach to stability analysis of soils is developed, in which the conventional limit equilibrium method is combined with the upper-bound theorem of limit analysis by variational technique and Lagrange’s multipliers procedure. This method is characterized by its flexibility of application to solve various stability problem in soil mechanics. Physical nature of this method and solution characteristics are examined. Finally, this procedure is applied successfully to assess the bearing-capacity of layered foundation, lateral earth pressure of cohesive backfills on retaining wall, and earthquake-resistant capacity of soil slopes. Some numerical results are given and meaningful conclusions are drawn.