Genetic diversity was examined in eight populations of the invasive plant Agasicles hygrophila in Jiangsu province using random amplified polymorphic DNA(RAPD) markers.A total of 99 discernible loci was obtained for all populations using 10 primers,36.3% of which were polymorphic (P_(PL)=36.3%).As analyzed by POPOGENE,average percentage of polymorphic loc(P_(PL)=26.2%),Nei’s genetic diversity(H_e=0.090 6) and Shannon’s information index(H=0.160 9) indicated that A.hygrophila had a relatively high level of genetic diversity.The proportion of the genetic differentiation among the A.hygrophila populations(G_(st)) was 30.88% and the gene flow was 1.118 9.The combined information from the analyses of genetic diversity and UPGMA indicated that genetic diversity of populations in Zhenjiang and Nanjing was the highest.As the genetic structure of A.hygrophila population was related with locality,in Nanjing,a center of the transportation,we should control spreading,migration and diffusion of the asexually propagates of A.hygrophila especially.