Abstract: Reyan 7-33-97(Hevea brasiliensis,Reyan 7-33-97)and RRIM600(Hevea brasiliensis,RRIM600)were large-scale of the extension cultivation of choiceness,and their karyotype analysis was important in breeding.Karyotypes Reyan 7-33-97and RRIM600 were analysed with the enzyme and low osmotic method.The karyotype formula of Reyan 7-33-97 was 2n=36=34m(4sat)+2sm.Which belonged to 2B type.As to RRIM600,the karyotype formula of RRIM600 was 2n=36=28m(4sat)+8sm.The karyotype RRIM600 was also belong to 2B type.The karyotype formulas of Reyan 7-33-97 and RRIM600 were relatively original during genome evolution.The study will provide cytological basis for the breeding,germplasm analysis and gene location of Hevea brasiliensis Muell.Arg.