Abstract: In order to improve the reliability of the fire damper in nuclear power plants, the application status and failure history of fire damper in several nuclear power plants were analyzed in this paper. The failure mechanism and maintenance strategy optimization of different fire dampers are studied by Failure Mode and Effect Analysis (FMEA) method. The results show that the annual inspection of appearance and action is optimized, and the task of regularly changing fuse element and electric mechanism is added, which can effectively reduce the failure rate of fire damper and ensure the safe and stable operation of nuclear power plants.