Objective:To study genetic diversity in endangered medicinal plant Radix Gentianae Macrophyllae of Gansu,then to provide theoretical evidence for the sustainable development and reseanable use.Methods:The-20℃Radix Gentianae Macrophyllae iced leaves for enzyme extraction,electrophoresis,staining and analysis POPGENE software.Results:9 of Radix Gentianae Macrophyllae wild populations of 151 individuals through the eight enzyme systems and 12 enzyme loci analysis showed that lower levels of genetic diversity existed in Radix Gentianae Macrophyllae.Each point the average number of alleles locus(A)was 1.1,the percentage of polymorphic loci(P)was 20.17,and the GST was 0.1352,suggesting that 86.48%of the total genetic diversity was distributed within populations.Conclusion:Considering the relatively low levels of genetic deversity in Radix Gentianae Macrophyllae populations and the many seedlings regenerating in the smallest population,we recommend in situ conservation in Tianshui,Ziwuling to maintain viable Radix Gentianae Macrophyllae populations in their original habitats.