In this study,the total genomic DNA were extracted with CTAB method,and then the genetic structure of the Arceuthobium sichuanense from 9 different populations was analyzed according to the sequence of internal transcribed spacer 1 (ITS1).1)Sixteen haplotypes (H1-H16) were observed from 62 ITS1 sequences,showing a low level of genetic diversity (h=0.678 5,π=0.005 9) in the populations of A.sichuanense.However,there were larger differences of the level of genetic diversity (h=0-1.000 0,π=0-0.009 4) among different populations.The AMOVA analysis showed that the genetic variation within populations of A.sichuanense,accounted for 51.37%,while the genetic variation among populations was 48.63%.2)Haplotypes of network showed that H1 and H12 were relatively original in this study.Also,two haplotypes were not shared among all of populations.H1 exists widely in six populations from Qinghai and Gansu,and H12 only exists in two populations from Sichuan.3)Population clustering based on maximum likelihood and medianjoining network based on maximum parsimony method indicated that the three populations from Sichuan are independent populations,while there is no significant differentiation between Gansu and Qinghai population.It is the first report about the genetic diversity and structure of A.sichuanense.The results will provide reference for the evolution and disease control of A.sichuanense.