Abstract: In this paper, we briefly introduce the types and the traits of clonal plants, review the characters of the genetic diversity and the genetic structure, and discuss the source of genetic variation in them. In a whole, the genetic diversity of clonal plants is much higher than that had been expected before. Although the genetic diversity is lower than their sexual congener, widely genetic m onomorphism has been rarely found. The genetic structure in clonal plant has some changes. Widely_distributed genotypes are scarce, most of them exist only within one population. The genetic variation among populations is extensive, and the genetic diversity among different clonal plant species varies. Besides the reproductive mode, some other factors such as geographic distribution, habitat, way of dispersal and population history also affect the genetic diversity of clonal plants.