Abstract:23 populations of the six species were collected from respective distribution range and were analyzed using random amplified polymorphic DNA (RAPD) markers. A total of 303 loci were obtained from 15 random primers. The cluster analysis basing on genetic distances demonstrated that the populations of every species were clustered together respectively. Then the populations of A. intramongolica were clustered together with the populations of A. ordosica, following with the populations of A. halodendron. It indicated that genetic relationships of this three species were the nearest, and it was more near between A. intramongolica and A. ordosica. The populations of A. sphaerocephala were clustered together with the population of A. songarica indicated that genetic relationship of the two species were near. A. wudanica was an independent branch, so the kinships between A. wudanica and others were far. The cluster analysis on the species demonstrated the same results. A. intramongolica was regarded as geographic subspecies of A. ordosica because of their populations being the nearest according to the cluster analysis, their genetic identity amounting to 0.964 1, their small calathide and similar morphological characteristic.