Abstract: In allusion to the difficulty of DC current prediction in the process of commutation failure recovery, firstly, the equivalent model of DC line was analyzed, the quantitative relationship between DC voltage on the rectifier side and the electrical quantity on the inverter side was established, and a method that can accurately predict the DC current change was proposed based on DC control analysis. Secondly, based on the prediction method of minimum off-area discrimination and DC current change, a subsequent commutation failure risk assessment model was constructed, and the trigger angle was quantitatively controlled according to the risk assessment results to suppress the occurrence of subsequent commutation failure. Taking the standard model of Conseil International Des Grands Reseaux Elecctriques (abbr. CIGRE) in the PSCAD/EMTDC platform as the test system, the simulation results under different fault types, severity and duration verify the accuracy of the proposed DC current prediction, subsequent commutation failure risk assessment and the effectiveness of the subsequent commutation failure suppression strategy.