The purpose of internal fire probabilistic safety assessment (PSA) is to evaluate the core safety risk caused by internal fire in nuclear power plant, which has been widely used in the world. Detailed circuit failure and spurious operation analysis is an important technical element in internal fire PSA. Circuit failure caused by internal fire is a special failure mode of nuclear power plant in the case of fire. It refers to the phenomenon of short circuit or open circuit caused by circuit damage in the case of fire, which may cause spurious operation or failure of nuclear power plant equipment, and then affect the normal operation of equipment, resulting in internal initiating events or affect the mitigation of accidents. The basis of detailed circuit failure and spurious operation analysis is to determine the list of equipment and multiple spurious operation combinations. Taking the detailed circuit failure and spurious operation analysis of HPR1000 internal fire PSA as an example. This paper focuses on the single equipment screening and multiple spurious operation combination screening methods and results in the detailed circuit failure and spurious operation analysis, and summarizes the screening methods and screening principles in detailed circuit failure and spurious operation analysis.