SSR markers were used to analyze the genetic diversity and structure,to explore the endangered causes of six Kingdonia uniflora populations at different elevations in Taibai Mountain.The results showed that:(1)Low level genetic diversity existed in K.uniflora populations.The percentage polymorphic band(PPB),Shannon’s information index(I) and Nei’s gene diversity(H) was 47.04%,0.241 6 and 0.161 4,respectively.Total gene diversity(H_t) was 0.419 0,and gene diversity within population(H_s) was 0.163 7.Gene flow(N_m) in the populations was estimated to be 0.527 4.(2)The genetic diversity of all studied populations decreased firstly and then rose with increasing elevation.(3)AMOVA analysis indicated that there were 66% variance among the populations,being consistent with the coefficient of gene differentiation(G_st=0.611 8).(4)Six populations were mainly clustered into two groups based on the genetic distance between populations.The populations at adjoining elevations firstly gathered,however,all six populations not clustered seriously according the geographical distance,which was consent with the Mantel test(r=0.341,P>0.05).