Abstract: The half-bridge sub-module cannot block DC short-circuit faults, and the blocking fault ride-through strategy has the disadvantages of getting the converter out of control and complexing the system restart process, which reduces the reliability of the modular multilevel converter. Therefore, a non-blocking fault ride-through strategy based on negative DC voltage control is proposed. In the strategy, after DC side short circuit fault occurs, the DC voltage is controlled to be negative by moving down the modulation wave, so as to realize the rapid removal of DC fault. In addition, to solve the problem of unbalanced capacitor voltage between output positive and negative level submodules in the process of the non-blocking fault ride-through, a double-sequencing control algorithm is proposed to realize the rapid equalization of capacitor voltage of submodules. At the same time, a systematic non-blocking fault ride-through strategy from DC fault to the restart of converter station is designed. The simulation results based on MATLAB/Simulink show that the non-blocking ride-through strategy based on negative DC voltage control can quickly block the DC fault current, and the capacitor voltage of the submodules remains a balance, which can realize the quick restart of converter.