Powdery mildew, caused by Blumeria graminis hordei, is currently the most serious foliar disease of barley in worldwide and reduced barley yield. The use of resistant cultivars is an efficient, economical and environmentally way to control of powdery mildew in barley. In this research a half diallel design was used for genetic analysis of resistance to powdery mildew (BGH) in barley. Six barley genotypes along with a landrace (Sahra) ranging from susceptible to resistance against BGH were used. The experiment materials were arranged in a randomized complete block design with three replications. Genetic analysis was applied in adult plant stage at field. The traits measured at adult plant stage were disease severity and area under disease prograss curve (AUDPC). The results indicated that additive-dominance model is adequate for both traits, but dominance effects were more important. Both traits were under control of one gene. In both traits, 104/110 ICARDA genotype was recognized as a resistance line containing resistante genes with dominance effect. Thus it has potential for obtaining superior lineages in selection programs for BGH resistance.