Since it is difficult to quickly control the internal energy of the converter, which may cause problems such as unbalanced energy between the arms in the modular multilevel converter based high voltage direct current (MMC-HVDC) system，this paper proposes a control strategy of MMC based on energy balancing control from the internal mechanism of the converter, optimizing the control of the current components of each arm. The control strategy can realize the coordinated control of the AC side current and the internal energy of the converter，and effectively reduce the internal energy unbalanced process caused by the converter during the system fault process. Finally, the MMC simulation model is built on MATLAB/Simulink，and the simulation results verify the effectiveness of the proposed control strategy.