[en] The features of the emergency power supply system of the 10 MW High Temperature Gas-cooled Reactor (HTR-10) are briefly introduced, and the reliability of the emergency power supply system of the HTR-10 is calculated using fault-tree analysis method. The calculating results are compared with those obtained using the standard nuclear power plant design method. All the results show that the emergency power supply system of the HTR-10 is not only with high reliability but also quite simple as well as economic