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, the paper proposes an AC side fault crossing method based on energy balance 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 imbalance process caused by the converter during the system transient process. Finally, the MMC simulation model is built on MATLAB/SIMULINK, and the simulation results verify the effectiveness of the proposed control strategy.