In order to suppress the continuous commutation failure of DC system, the main reason of the first commutation failure is the rise of DC current and the decrease of AC system voltage at the inverter side. The action characteristics of the control system and the law of the electric quantity change in the recovery phase after the first commutation failure are studied. It is concluded that during the recovery phase of the commutation failure, the fast recovery of the DC voltage at the inverter side will cause the fast rise of the DC current command value, and the inverter side will switch to the constant current control. The influence of the DC current rise on the turn off angle which is not considered in the control process results in the control loses of the extinction angle which leads to the failure of DC continuous commutation. Therefore, an optimal control strategy of DC current command value considering the turn off angle is proposed, which combines with low-voltage current limiting control to suppress the occurrence of continuous commutation failure. Finally, the effectiveness of the proposed control strategy is verified by PSCAD / EMTDC simulation software and CIGRE HVDC model simulation.