In order to obtain the natural frequency and the vibration mode of rectifier cabinet for nuclear power generating stations, the vibration theory of the structural morphology is elaborated, the natural frequency of the cabinet is researched, and the finite element model of the cabinet is set up by ANSYS. The natural frequency and the vibration mode of the rectifier cabinet for nuclear power generating stations are obtained by modal analysis. It is a reference for further dynamic analysis through the analysis method and the obtained results.