A new analysis method of structural reliability based on universal generating function (μ function) is produced, its basic thinking is based on the z transform of discrete signal processing, it transforms random variable into μ function model which describes its uncertainty. And it utilizes favorable properties and logical relation algorithm of μ function to pass the input uncertainty to the output uncertainty. According to the reliability indexes of μ of μ function model is established in order to solve the computing problem of functional algebraic operation of μ function. Compared to Monte-Carol method, the idea based on z transform transforms the problems of discrete real domain into the problems of discrete complex domain, and conducts reliability analysis in domain which is similar to discrete complex domain. The calculating examples verify high efficiency and feasibility of the proposed method.