The invention provides a control optimization method and device for suppressing high-voltage direct current transmission commutation failure and belongs to the power transmission and distribution technical field. With the method and device adopted, the problem of high risk of commutation failure caused by a condition that triggering angle control output dose not satisfy a commutation requirement when a high-voltage direct-current transmission alternating-current system malfunctions in the prior art can be solved. The method includes the following steps that: whether an alternating-current fault occurs on an inverter station is detected; when it is detected that an alternating-current fault occurs on the inverter station, the triggering angle of a rectifier station is corrected, so that the triggering time of the thyristor of the rectifier station can be changed; the commutation voltage zero-crossing offset quantity and commutation voltage amplitude change quantity of the inverter station are obtained; and the turn-off angle adjustment value of the inverter station is calculated according to commutation voltage and the commutation voltage zero-crossing offset quantity, and the setting value of the fixed turn-off angle of the inverter station is adjusted. The control optimization method and device provided by the embodiments of the present invention are applied to optimizing the commutation process of high-voltage direct current transmission.