For reduces as far as possible the number of failure by the software design process dissemination, put forward a new software design method based on fault-tree analysis. On the basis of fault-tree analysis, it should its import software design development process according to these characteristic of static and dynamic of software, and taking example process modeling and analysis. The result shows that the method has low complexity, high accuracy of calculate, process simple of modeling, suitability for small-scale system. The method can advance reliability and security in the development process of maritime test and control.