惯导系统是导弹的核心组成部分，其工作过程呈现一系列动态特性。为了获得惯导系统发生事故的可能性并查出可能导致事故的薄弱环节，在利用动态故障树方法对其进行安全性分析的基础上，建立了惯性平台倒台事故的动态故障树模型。然后将动态故障树模型模块化为独立的静态子树和动态子树，并分别利用二元决策图及Markov状态转移法进行了分析，经综合分析后得到了倒台事故在整个寿命周期内发生的概率。通过仿真实验分析了导致倒台事故的主要因素，验证了所用方法在惯导系统安全性分析中的适用性。

Inertial navigation system is the critical component of missile, and present dynamic character during its work. For getting the possibility of mishap of inertial navigation and find its weak link, Dynamic Fault Tree (DFT) model of collapse of inertial platform is built based on safety analysis used Dynamic Fault Tree. Then the model is modularized into independent static subtrees and dynamic subtrees; Binary Decision Diagrams (BDD) and Markov method are applied to process them respectively; the possibility of collapse of inertial platform in all its life is get after comprehensive analysis. Though simulation experiment, the major cause of collapse of inertial platform is found, and the applicability of DFT in the safety analysis of inertial navigation system is validated.