离散结构的形状优化问题，设计变量是不同性态的连续／离散混合变量，优化收敛困难。本文利用遗传算法实现其全局最优设计，以空间２５杆桁架结构为例，进行了多变量、多工况的结构形状遗传优化设计。为减少结构重分析次数，引入了Ｓｔｅａｄｙｓｔａｔｅ算法。结果表明结构形状的遗传优化设计方法是可行的。 For the shape optimization problem of discrete structures, design variables are continuous/discrete mixed variables of different behaviors, and it is difficult to optimize convergence. This paper uses genetic algorithm to achieve its global optimal design. Taking the spatial 25-bar truss structure as an example, the multi-variable and multi-condition structural shape genetic optimization design is carried out. In order to reduce the number of structural reanalysis, Steadystate algorithm was introduced. The results show that genetic optimization design method of structural shape is feasible.