面对日益复杂的飞机系统，传统的安全性分析方法对复杂系统间的不安全交互行为和危险源的识别能力不足。为有效评价持续适航阶段的飞机系统安全性，提出了一种融合系统理论过程分析（system theory process analysis, STPA）和动态故障树（dynamic fault tree, DFT）的改进的STPA安全性分析方法和评价模型。模型采用STPA识别出不安全控制行为和致因因素，并将其与动态故障树分析方法相融合，以事故致因理论优化致因分析方法，计算得出不安全控制行为发生概率并确定系统潜在危险的关键致因因素。以飞机起落架系统为例进行分析验证，结果表明，改进后的STPA分析方法可以准确地对系统危险进行识别和分析，为持续适航阶段的安全性分析提供支持。

In the face of increasingly complex aircraft systems, the traditional safety analysis methods are insufficient for identifying unsafe interaction behaviors and hazard sources among complex systems. In order to effectively evaluate the safety of aircraft systems in the continuous airworthiness phase, an improved system theory process analysis (STPA) safety analysis method and evaluation model that integrates STPA and dynamic fault tree (DFT) were proposed. STPA was used to identify unsafe control behaviors and causal factors, which were integrated with dynamic fault tree analysis method. The accident causation theory was used to optimize the causal analysis method, calculate the probability of unsafe control behaviors occurring, and determine the key causal factors of potential system hazards. The results show that the improved STPA analysis method can accurately identify and analyze system hazards and support the safety analysis in the continuous airworthiness phase.