Abstract: The similarities among 20 Chinese desert plant floras are studied by using clustering analysis with Jaccard's similarity coefficients in this paper.The results suggest that these floras can be classified into 3 groups of the Mongolica Desert Plant Zone,the Northwest Desert Plant Zone and the North China Desert Plant Zone.According to results obtained from the clustering analysis based on similarity coefficients at family,generic and specific levels,Hexi Corridor,front of Qilian Mountain and edge of Tengger Desert,Tuha Basin and Tsaitam Basin are more isolated.The results coincide with characteristics of floras and traditional demarcation of typical vegetations.

Key words: Chinese desert flora, Jaccard's similarity coefficient, maximum spanning tree, clustering analysis