Abstract: ObjectiveGenetic diversity of Sporisorium scitamineam from main sugarcane growing area of Guangxi was studied, in order to provide new ideas for comprehensive control of sugarcane smut. MethodS. scitamineam was collected from main sugarcane growing areas of Guangxi, and genomic DNA were extracted from 70 haploid strains. Optimized random amplified polymorphic DNA(RAPD) reaction system and 10 RAPD primers screened deliberately were used to de-tect polymorphism of S. scitamineam by PCR amplification. Then, according to electrophoretogram, Cluster analysis was conducted to construct phylogenic tree with NTSYS2.1 software. ResultThe results showed that, 10 RAPD primer pair could amplify 4-11 bands each, with a total of 77 bands, each band ranged from 150 to 3000 bp in length, but only 6 polymorphic sites were detected, which accounted for a polymorphic ratio of 7.79% in population. The genetic similarity coefficient of 70 S. scitamineam strains ranged from 0.96 to 1.00, and those strains were clustered into 2 clusters at genet-ic similarity level of 0.96, the first cluster was comprised of 2 strains collected from Xiaoyi town of Hengxian county, while the remaining 68 stains were clustered into the second cluster. ConclusionS. scitamineam is at low level of genetic differentiation in Guangxi. Polymorphism of S. scitamineam had no significant correlation with its geographical origin, hosts and mating types.