Abstract: In this paper, the floristic constitute and geographical elements of families of Xinjiang's spermatophytic flo-ra were analyzed. The results showed: (1) There was 3 423 species belonging to 715 genera and 100 families inXinjiang. In view of the quantitative feature, there markedly were 16 dominant farmilies, which occupies only 16% of total farmilies, but they consist of 482 genera and 2 429 species and posses 73.8% of total genera and 79.3% of total species respectively. (2) On the geographical elements of families, the cosmopolitan familieswere dominant (35.0%), they indicated that Xinjiang's flora was existed obvious transition; but the temperatefamilies (52.0%) were more predominant, for example, the typical temperate distribution has 23 families, tropical to temperate has 26 families, and subtropical to temperate has 3 families. Then, the tropical and tropicalto subtropical distribution families are only 13 (13.0%). All those were adapted with the latitude zone in Xin-jiang, they reflected that plant distribution was closely related to the local climatic conditions. (3) The typicalfamilies of Xinjiang's flora was very special, because they were also included in some comopolitan families, e. g. Chenopodiaceae, Cruciferae, Polygonaceae, Caryophollaceae, etc., which differed from tropical or subropi-cal floras. Of course, a great of typical and dominant families of Xinjiang's flora still were temperate families orthose mainly distributed in temperate zone, e. g. Tamaricaceae, Salicaceae, Papaveraceae, Zygophyllaceae, Ranunculaceae, Plunbaginaceae, Pinaceae, Ephedraceae, Rosaceae, etc., and above cosmopolitan farmiliesmainly distributed in temperate zone, so all evidences indicate that Xinjiang's flora was characterized by the typ-ical temperate properties.

Key words: Xinjiang, spermatophytic flora, family, geographical element