The invention discloses a C-MMC static voltage equalization control method based on energy-obtaining power supply control. First, the capacitor voltage of each C-MMC sub-module is collected, the average value thereof is obtained, and by comparing the voltage of the C-MMC sub-module with the target voltage, an energy-obtaining power supply modulation signal that satisfies the voltage balance between the sub-modules is obtained. Then, the average value of the two capacitor voltages in the sub-modules is taken as the target of balancing the two capacitor voltages in the sub-modules. The capacitorvoltage value and the target value are compared to obtain the energy-obtaining power supply modulation signal that satisfies the balance of the two capacitor voltages in the sub-modules. The modulation signal is compared with a triangular carrier to obtain a control signal of a flyback circuit in an energy-obtaining power supply. Depending on the control signal, the input current of the energy-obtaining power supply is adjusted and the capacitor voltage of a power module is adjusted indirectly. No additional circuit is needed, and the control method is simple, which is very important for reducing the loss of the system and ensuring the normal startup of the system.