为了完成30 m光学红外望远镜(TMT)三镜支撑系统(M3CA)抗震性能分析，编制了地震波拟合软件，拟合出符合设计要求的地震时间历程，并基于时程分析方法进行了结构的地震有限元仿真。基于具有随机相位的三角级数理论编制了拟合地震波的软件，针对拟合精度低的问题引入幅值校正方法，使拟合的地震波谱与设计响应谱的平均偏差在4%以内；基于该系统的设计响应谱，拟合了返回周期为200年的地震时间历程；利用时程分析方法对结构进行了有限元仿真。仿真结果表明，三镜相对于三镜室最大位移为1.881 mm；三镜上的最大应力为0.27 MPa，发生在镜子的侧支撑位置处；支撑结构的最大应力为310.54 MPa，发生在侧支撑杆上。根据材料性能，三镜及侧支撑杆的最大应力均在材料的极限应力之内，故在返回周期为200年的地震发生时可保证系统的安全性。编制的程序拟合精度高，充分考虑了各种因素，结合有限元时程分析，为大型光电设备的地震分析积累了经验。

In order to complete the seismic analysis of thirty meter telescope (TMT) tertiary mirror cell assembly (M3CA), seismic wave fitting software has been developed, seismic time histories are obtained through the software, and then seismic analysis has been done based on time history analysis. The software fit for the seismic wave is developed based on the theory of trigonometric series with random phase, amplitude correction is introduced to increase the fitting precision, the average difference between fitting seismic wave spectrum and design response spectrum is less than 4%; then, according to the design response spectrum with average return period of 200 years, seismic time histories are fitted; finite element method (FEM) analysis is carried out based on time history analysis method. The simulation results illustrate that the displacement of tertiary mirror relative to the cell is 1.881 mm; the maximum stress on the mirror is 0.27 MPa which occurs on lateral supporting position; the maximum stress of the support system is 310.54 MPa and appears on the lateral support rod. Compared with material characteristics, the maximum stresses are all within material stress limitation, which indicates that the security will be assured when 200-year return period earthquake happens. The program obtains a high fitting precision and various factors are considered. Combined with the finite element analysis, it will provide experience for seismic analysis of large photoelectric equipment.