[en] Based on analyzing the modulator's hardware and the characters of the circuit, the 110 MW pulse modulator's controller has been designed. And the purpose of this work was to ensure the modulator's stability, credibility and safety, and to make the modulator accord with the control-demand of the 100 MeV linear accelerator. After being debugged and tested, it was found that the design achieves the request of controlling and guarding the modulator safely. (authors)