The invention discloses a multi-direct-current power emergency support coordination control strategy. When large-power-region extraneous electricity loss in a grid or a large power unit trip fault isgenerated in a multi-direct-current feed-in power grid, if a power shortage is greater than the maximum bearable unbalanced power of a regional power grid, direct current power injected into an alternating current system is rapidly and effectively adjusted by using other non-fault direct current emergency power support capabilities in the grid, and the power shortage of a receiving end power gridfed by multiple direct currents is sequentially distributed to an asynchronous interconnection transmitting end power grid through the direct current. The strategy can be based on the current operating state of an alternating current and direct current system and the inherent characteristics of an alternating current and direct current power grid, and the emergency support power amount for multi-circuit direct currents in the grid is determined in online and real-time modes. On one hand, a direct-current short-time maximal emergency support capability is ensured to be fully utilized; on the other hand, the occurrence of chain accidents caused by a unreasonable emergency control instruction is avoided and the transient stability of the power grid is increased.