Samples of corn southern leaf blight were collected from 5 locations of Xinxiang region from 2013 to2015 years.Among them,413 strains of Bipolaria maydis were identified with the identification hosts, and population structure of race of Bipolaria maydis was analyzed.The results showed that there were four races of Bipolaria maydis,which Race T,Race C,Type S and Race O.Isolation frequency of Race O was significant higher than those of the other races.It is suggested that Race O was the dominant race of B.may...