In order to formulate conservation strategies of this species,We assessed the genetic diversity of G.littoralis with total 241 samples of 10 populations using molecular marker ISSR analysis.The result revealed that high levels of genetic variations occurred within and among populations (PPB=84.21%,Ne＝1.562 8,I^*＝0.866 3,h^*＝0.342 5).The genetic differentiation coefficient (G_ST) among populations was 0.205.Analysis of molecular variance (AMOVA) demonstrated that 25.91% of genetic diversity was found among populations,74.09% of genetic diversity was found within populations.The value of gene flow (N_m) was 1.939 1.It is indicated that the endangered status of this species is probably due to destruction of habitats of the wild populations,rather than a loss of the genetic diversity.