The invention discloses a construction method of a power impact simplified model under a direct current fault. The construction method comprises the steps of 1, obtaining the actually measured data ofthe output power of a direct current system when a direct current fault occurs; 2, judging a fault according to the actually measured data; and 3, establishing the model. Specific to complexity and diversity of a power fluctuation process under the direct current fault, the power impact simplified model under the direct current fault is established by virtue of summary of power impact forms underdifferent faults; the model remains the power impact key characteristic under the direct current fault; and meanwhile, the model is simple and practical, and can be applied to simulation study of call wire power oscillation of an alternating direct current power grid.