Two types of sampling plots of seabuckthorn(Hippophae rhamnoides) communities were investigated in Pengyang County of Ningxia region by a typical sampling method to study the characteristics of community structure and biodiversity.Composition and dominant species of each community were analyzed by the importance value of species as an index.The number of indi-viduals and the importance value,as well as Sorensen’s similarity coefficient,Shannon-Wiener diversity index,Pielou’s evenness index and Simpson’s dominance index,were used as indices to compare characteristics of community structure,similarity and biodiversity between plantations and natural forests of seabuckthorn.The results indicate that the importance values of species of natural seabuckthorn communities were dispersed and the difference between dominant species was not statistically significant.Diversity indices of natural seabuckthorn communities reflected by species richness and evenness were higher than that of plantations.Community structure of natural seabuckthorn forests is more complex.We propose that natural forest can be used as sample to guide selection of plant species in silviculture in order to improve biodiversity of plantation. Two types of sampling plots of seabuckthorn (Hippophae rhamnoides) communities were investigated in Pengyang County of Ningxia region by a typical sampling method to study the characteristics of community structure and biodiversity. Composition and dominant species of each community were analyzed by the importance value of species as an index. The number of indi-viduals and the importance value, as well as Sorensen’s similarity coefficient, Shannon-Wiener diversity index, Pielou’s evenness index and Simpson’s dominance index, were used as indices to compare characteristics of community structure, similarity and biodiversity between plantations and natural forests of seabuckthorn. The results indicate that the importance values ​​of species of natural seabuckthorn communities were dispersed and the difference between dominant species was not significant significant. Diversity indices of natural seabuckthorn populations reflected by species richness and evenness were higher than that of plantation s.Community structure of natural seabuckthorn forests is more complex.We propose that natural forest can be used as sample to guide selection of plant species in silviculture in order to improve biodiversity of plantation.