The invention belongs to the fields of plant genetic engineering and molecular plant breeding, and provides a recombinant vector comprising the CmWRKY15-1 gene, transformed cells as well as breeding and identification methods of chrysanthemum morifolium of trans-CmWRKY15-1 gene and an application of the chrysanthemum morifolium of trans-CmWRKY15-1 gene. The breeding method of the the chrysanthemummorifolium of trans-CmWRKY15-1 gene comprises the following steps: (1) cloning the chrysanthemum morifolium CmWRKY15-1 gene; (2) constructing a plant expression vector PBI121-CmWRKY15-1; and (3) transforming the chrysanthemum morifolium via an agrobacterium EHA105-mediated leaf disc method. Based upon PCR and quantitative RT-PCR detection on the transformed plant (chrysanthemum morifolium), it isproved that the CmWRKY15-1 gene is integrated into genome DNA of the transgenic plant and undergoes transcription. By conducting disease resistance detection on the transgenic plant, the capacity ofthe transgenic plant in resisting white rust is obviously improved; therefore, a feasible method is provided for breeding the novel variety of chrysanthemum morifolium.