The invention discloses a phase locking and frequency stabilizing gyrotron with a periodic multiple-conductor structure, and belongs to the technical field of high-power microwave and millimeter wave sources. The phase locking and frequency stabilizing gyrotron with the periodic multiple-conductor structure comprises a resonator, an output gradient waveguide and an even output waveguide, wherein the resonator is provided with an electron beam channel and injection waveguide holes. The phase locking and frequency stabilizing gyrotron with the periodic multiple-conductor structure is characterized in that in a resonant cavity of the resonator, at least three conductor structures are evenly arranged in the radial direction around the electron beam channel, and the injection waveguide holes are located between two adjacent conductor structures. The phase locking and frequency stabilizing gyrotron with the periodic multiple-conductor structure has the advantages that an injection signal can be effectively converted to a working mode of the gyrotron through the multiple-conductor structure, and therefore modulating actions are compulsorily conducted by electron beams according to the injection signal, the electron beams can only generate the modulation and the output of the injection signal, and an output signal achieves phase locking and frequency stabilizing.