Abstract: A new reliability sensitivity factor is constructed by using the standard deviation of reliability sensitivities,based on the analysis and derivation of reliability sensitivities.Different from the traditional sensitivity factor,the new one can reflect the importance difference of all stochastic variables to structural failure probability,and also can represent the error caused by a variable or multiple variables considered as a constant.According to the conclusion,all helpful information from the effect of all stochastic variables on structural failure probability can be recognized by performing a reliability sensitivity analysis.This method can thusly improve the calculation efficiency and reduce the analysis difficulty greatly.The paper illustrates and verifies the conclusion by numerical examples in the final.