In order to enhance the beam transmission efficiency, intensity and stability of SFC (Sector Focusing Cyclotron), the power supply must be stabilized with long-term variations at a magnitude of 10-4. A high-precision and stable power control system was designed and optimized In order to enhance the beam transmission efficiency, intensity and stability of SFC (Sector Focusing Cyclotron), the power supply must be stabilized with long-term variations at a magnitude of 10-4. A high-precision and stable power control system was designed and optimized