Powdery mildew caused by Erysiphe graminis f. sp. tritici is one of the most important wheat diseases in many regions of the world. Breeding for resistant cultivars has been proved to be an effective and environmentally safe method to control diseases in wheat production. It is necessary to search for more resistance genes for the diversification of resistance genes in wheat breeding. An Isreali wild emmer wheat (Triticum dicoccoides) accession "G-305-M" was found resistant to the prevailing E. graminis f. sp. tritici isolate Race No. 15 in Beijing region. The powdery mildew resistance has been transferred from G-305-M into common wheat by crossing and backcrossing (G-305-M/781//Jing 411* 3). Genetic analysis showed that the resistance was controlled by a single dominant gene at the seedling stage. A segregating BC2F3 family of the cross "G-305-M/781//Jing 411* 3" with 167 plants was chosen for SSR analysis. Totally 96 wheat microsatellite primer pairs were screened, only one primer pair WMS570 could generate polymorphic DNA fragments between the resistant and susceptible plants. After evaluating this polymorphic marker in the segregating population, the microsatellite locus Xgwm570 mapped on chromosome 6AL was found to be linked to the resistance gene, with the estimated genetic distance of 14.9 +/- 3.0 cM. Based on the origin and chromosomal location of the gene, it is suggested that the resistance gene derived from G-305-M should be a novel Pm gene and is temporarily designated MlG.