Wheat powdery mildew is a fungal disease that impacts severely on production of wheat. Identification of wheat disease-resistant germplasm and exploiting of wheat powdery mildew resistance gene from existing resources is required for sustainable improvement in disease resistance. In this study, a local wheat variety Siyuehuang with resistance to powdery mildew was identified from wheat germplasm resources in Shanxi Province. The genetic populations of Siyuehuang crossed with the powdery mildew susceptible cultivars Jinmai47 was developed to identify and analyze by artificial inoculation of single species at seedling stage. The resistance gene carried from Siyuehuang was mapped by BSA(bulked segregant analysis) and 90K SNP(single nucleotide polymorphism) chip scanning. The results showed that the resistance of Siyuehuang to wheat powdery mildew was controlled by a pair of dominant nuclear genes, and the inheritance pattern was in accordance with Mendelian inheritance law, temporarily named PmSYH. SNP microarray results showed that polymorphic SNP markers were mainly concentrated in the 110 ~ 140 Mb segment of the short arm of wheat chromosome 7D. SSR (Simple Sequence Repeats) molecular markers were developed in this genomic section, and linkage screening was performed by using resistant subpopulation and susceptible subpopulation. Six SSR markers linked to PmSYH were obtained, and the F2 population of Jinmai 47 / Siyuehuang was genotyped using these 6 SSR markers. Finally, the Powdery mildew Resistant gene PmSYH was mapped in the physical section 132.57 Mb ~ 137.47 Mb on the short arm of wheat chromosome 7D. The flanking marker were Sxau7DS-37 and Sxau7DS-48 with genetic distances 1.8cM and 3.1cM, respectively. Compared with other genes on wheat chromosome 7D, PmSYH is a new powdery mildew resistant gene. This study enriched wheat powdery mildew resistance gene resources, which has a certain value for the improvement of wheat powdery mildew in the northern winter wheat region.