Abstract: The gyrotron is a microwave vacuum electronic device based on electron cyclotron resonance (ECR), used to produce high power millimeter microwave in controlled thermonuclear fusion research, radar and other important application fields. According to the requirements of anode power supply of 1 MW/105 GHz gyrotron for Tokamak electron cyclotron resonance heating (ECRH), the high-frequency switching power supply technology and pulse step modulation (PSM) were used to develop the solid anode high voltage power supply. The control algorithm of voltage regulation and modulation function of anode high voltage power supply was expounded, and the design was verified by experiments. The output parameter of the anode power supply can reach 35 kV/200 mA with three kinds of output models, including single pulse, multi pulse modulation and six preset level of waveform. Its rise time can be adjusted within 3 ms. The maximum modulation frequency is 1 kHz and regulation accuracy within 100 V. The designed control method can also be applied to other high power microwave sources.