The invention provides an anticipated fault assist decision-making method and device of an ultrahigh-voltage DC circuit. The method comprises the steps of calculating influence of assist decision-making adjustable measure on an active power of out-of-limit equipment, and acquiring a heavy-load equipment list; determining an assist decision-making strategy; and verifying the assist decision-making strategy, and determining adjustable margin of heavy-load equipment in the heavy-load equipment list. With the technical scheme provided by the invention, power flow transfer caused by an ultrahigh-voltage direct current anticipated fault is finely considered, heavy-load or out-of-limit power grid equipment caused by the ultrahigh-voltage direct current anticipated fault can be accurately judged, a cost coefficient of an optimal control target is set based on an optimization algorithm, the priority of the ultrahigh-voltage fault adjustment strategy is considered already, the ultrahigh-voltage direct current anticipated fault assist decision-making strategy measure is automatically generated by optimal calculation, on one hand, the heavy-load/out-of-limit equipment is eliminated, and on the other hand, the frequency of a power grid can be recovered to a normal level as soon as possible.