The utility model is suitable for an online digital state detecting and monitoring technology of power equipment, belongs to the key technical field of million-kilowatt-class nuclear power stations, and provides a reliability detecting device of a miniature fuse used for a nuclear power station. The device comprises an industrial personal computer, a program-controlled constant-current source, an acquiring card, a tester, a fuse and a programmable controller, wherein the industrial personal computer is respectively connected with the program-controlled constant-current source, the acquiring card and the programmable controller; the program-controlled constant-current source is respectively connected with the industrial personal computer, the acquiring card and the tester; the acquiring card is respectively connected with the industrial personal computer, the program-controlled constant-current source and the tester; and the tester is respectively connected with the program-controlled constant-current source, the acquiring card and the fuse. By using the reliability detecting device of the miniature fuse used for the nuclear power station, the performance of a tested fuse can be accurately judged according to the acquired test data, thus, risks of turbine trip and reactor scram are reduced, and the safety and the reliability of the nuclear power station are improved.