The present invention discloses a method and a system for reducing an extra-high voltage direct current non-fault layer commutation failure risk, belonging to the field of power systems. The method comprises the steps of: obtaining parameters of a layered feed-in extra-high voltage direct current series-parallel power grid, and calculating commutation failure features of a fault layer and a non-fault layer of the layered feed-in extra-high voltage direct current series-parallel power grid; obtaining parameters of the non-fault layer of the layered feed-in extra-high voltage direct current series-parallel power grid, and calculating a critical direct current idcr of commutation failure prediction linkage control according to the parameters of the non-fault layer; performing prediction linkage control for the layered feed-in extra-high voltage direct current series-parallel power grid; determining whether)to perform predication control or not according to the commutation bus voltage anddirect current change of the layered feed-in extra-high voltage direct current series-parallel power grid; and simulating and verifying the prediction linkage control extra-high voltage direct currentnon-fault layer commutation failure risk and linkage control parameters. The method and the system provided by the invention can effectively reduce the risk of the non-fault layer inverter commutation failure caused by disturbance of the fault layer and can reduce the active impact on the power grid caused by direct-current power fluctuation due to disturbance.