Erianthus rockii is the most important wild resource in sugarcane germplasm,which mainly distributes in Yunnan province.To well utilize the germplasm in breeding program,it is necessary to understand its genetic background.In this research,41 clones from national nursery of sugarcane germ were amplified with 10 informative AFLP primers.In total,860 bands were detected,629 of which were polymorphic,36 of which were specific bands,and rate of polymorphic bands was 0.73.The results of genetic similarity coefficients,UPGMA cluster,and principal component analysis showed that 41 sugarcane clones were divided into three groups at 0.715 of genetic similarity coefficient:Yundian 07/23 was only grouped into group A and should be further identified due to its back hair on the sheath different from others,group B included three sugarcane clones from high altitude area,group C included 37 sugarcane clones,containing of 30 from southwest of Yunnan,and 7 from other region.Groups C was divided into 4 sub-groups at 0.738 of genetic similarity coefficient,and the cluster relation was obviously reflected the geographic distribution of the clones.Sub-group C4 was divided into 4 sub-sub-groups at 0.765 of genetic similarity coefficient.Yundian 07/9/1 and Yundian 99/4 in sub-sub-group C4-3 were the most similar,indicating that two clones were duplicate.Sub-sub-group C4-3 included three branches according to 0.773 of genetic similarity coefficient.Principal component analysis for all clones indicated same result obtained from genetic similarity coefficients analysis.Therefore,complex geographical ecological environment is important factor to the genetic diversity and geographical distribution of E.rockii clones.