Thirty-eight isolates of Curvularia lunata, the causal agent of Curvularia leaf spot, were collected in 9 corn-growing locations throughout four provinces of Northern China during 2003 ~ 2004, to determine their pathogenicity on host differentials (Shen135, CN165, Mo17, Luyuan92, 78599-1,Ye478, B73, E28 and Huangzaosi).The isolates were grouped into 3 different pathogenic types (Ⅰ,Ⅱ and Ⅲ) based on their infection types on the host differentials and disease indexs.Genetic analysis of within and between pathogenic types by universally primed PCR (UP-PCR) revealed high genetic diversity in C.lunata population.A phylogenetic dendrogram was generated by the UPGMA method based on the average similarity coefficient between pathogenic type groups using program of the NTSYSpc 2.10s.Six clusters (A, B, C, D, E and F) were resolved at the 0.64 similarity level.There were 11isolates in pathogenic type Ⅰ (55%) which belong to cluster A (68.75%), pathogenic type Ⅱ (68.75%) also had 11 existing in cluster B, C, D, F (52.38%), pathogenic Ⅲ (100%) had 1 exiting in cluster F (100%).Our current studies demonstrated UP-PCR is an useful tool for identifying pathogenicity of C.lunata.