The invention discloses a continuous commutation failure suppression method and device based on a multi-feed DC system, and belongs to the field of power systems. The commutation failure of an inverter valve group is detected according to the measured value of a shutdown angle; after the delay time is preset, the current time enters the commutation failure recovery phase and an effective trigger control signal is obtained; a conversion signal is outputted according to an effective trigger control signal; a VDCOL controller converts to AC-VDCOL control from DC-VDCOL control; a duration signal is outputted according to DC voltage and commutation voltage; whether the duration signal is valid is judged, and if so, continuing to maintain the AC-VDCOL control; otherwise, a cut-back signal is outputted; and the VDCOL controller switches to the DC-VDCOL control from the AC-VDCOL control according to the cut-back signal,. The method and the device can effectively suppress the problem that the continuous commutation failure of the multi-feed DC system leads to a long fault recovery time.