针对地震动随机场特性进行解析展开，提出一种有效的变界展开方法，同时将频率相关的非线性方程精确线性化，且只须一次分解给定频率相应空间随机场即可直接进行整个频域随机场分析的效果。计算结果表明，该方法不但计算简单，而且具有截断误差小的特点，通常取解析展开的前五项即可满足工程需要。该方法非常适应大型结构多点地震动随机输入分析。 According to the characteristics of ground motion random field analysis and expansion, an effective method of boundary expansion is proposed. At the same time, the frequency-dependent nonlinear equations are accurately linearized and the frequency The effect of domain random field analysis. The calculation results show that this method not only has simple calculation, but also has the characteristics of small truncation error. Usually, it takes the first five items of analysis and expansion to meet the project needs. The method is very suitable for large-scale multi-point seismic random input analysis.