Abstract: Phylogenetic analysis of the Brn1 gene sequence of Exserohilum rostratum with great morphological variations were conducted. In the phylogenetic tree of nucleotide sequences, E. rostratum forms a monophyletic group with other Exserohilum species, which could be separated with the genera Bipolaris and Curvularia. The distance matrix was calculated using DNADIST. The smallest genetic distance value between tested E. rostratum strains was 0.0078. And the largest genetic distance value was 0.0197, which was smaller than the largest intraspecific genetic distance value, 0.0242. The results indicated that the Brn1 gene sequences were suitable for Exserohilum rostratum species identification.