Abstract: Based on structural mechanics,the internal force is obtained for the initial structure and the structureat the each failure state before it yields by a collapse mechanism.Thus, the repeated modification of global stiffness matrix andreverse node force can be avoided in the process of stochastic reliabilityanalysis. The partial derivatives of the limit state function to eachvariable can be obtained from the global stiffness matrix and the load vector of the initial structure, which isadvantageous for developing computer programs. It is shown that the result isthe same as using the other reliability method basedstochastic finite element. However, the efficiency is greatly improved.