The invention provides a rack structure optimization method applicable to multiple direct current emergent power support. The method comprises the steps of (1). according to characteristics of primary energy and load power consumption, establishing a rack and typical operation mode data of an alternating current-direct current hybrid target planning power grid; (2). evaluating power grid characteristics; (3). studying out an alternative rack optimization scheme; (4). conducting comprehensive technical evaluation on an alternative power grid optimization scheme; (5). conducting technical and economic analysis on the alternative power grid optimization scheme; and (6). determining the rack optimization scheme. By the aid of the rack structure optimization method applicable to multiple direct current emergent power support, the scientificity of the multiple direct current output or feeding power grid rack structure optimization can be improved, and the method provides important technical support for the establishment of multiple direct current output or feeding power grids which are firm in rack, flexible to adjust and reliable in operation.