When analyzing the multi-state fault tree of large and complex systems,the traditional method of building fault tree manuallycannot meet the requirements of building the multi - state fault tree of large and complex systems because of its disadvantages such asheavy workload,error - prone and poor reusability. In order to make up?for many shortcomings of manual tree building, computerautomatic tree building has been listed as the key research object by reliability engineers. However,there is?
no universal automatic faulttree building idea and algorithm,especially in the processing and analysis of complex structures such as feedback,and the existing researchhas not been able to provide a standardized processing method. In order to solve the above problems, we propose to standardize andpackage the fault characteristics of parts in the form of component models,so as to realize the free combination and reuse of componentfault models. On this basis,we propose a fault tree automatic algorithm flow that can solve the series-parallel system and looped system,and realize the processing of complex system structure. Combined with the cooling system,we describe the system modeling process andthe steps of the tree building algorithm. Finally,the consistency of the tree building results verifies the correctness of the method. For thefault tree construction of large and complex systems,the proposed method can reduce the workload of reliability engineers,improve thequality of tree construction,and help to form a unified standard in the industry.