In order to meet the multi-type multi-task trajectory simulation work, improve the trajectory simulation efficiency, and standardize the trajectory simulation program, a general-purpose software system for missile trajectory simulation has been developed. Using the C++ language, the standard trajectory database, the standard trajectory model and the standard interface have been established. The object-oriented programming method and the generic modular design idea have also been used. In the system there are three main features which are the easy-to-replace modules, the well-designed human machine interface and the good practicality. The initial application showed that it was competent enough to solve the trajectory simulation problem of several types of ground-to-air missile. The simulation efficiency has been improved and the general purpose has been achieved.