In order to enhance the efficiency of structural reliability- based optimization design,a PSO- DE hybridalgorithm is proposed on the basis of search features of the particle swarm optimization (PSO) and differential evo-lution (DE) algorithms.This algorithm overcomes the premature convergence of basic PSO algorithm.Moreover,by combining the PSO- DE hybrid algorithm with the structural reliability- based optimization theory,an optimization model is established to minimize the structure mass under the constraint of structural system failure probability.Caseanalyses show that,in comparison with the basic PSO algorithm,the proposed PSO- DE hybrid algorithm improves the convergence rate and the computational accuracy,and the algorithm is easy to implement with strong robustness.