Abstract: A detailed floristic phytogeographical characteristics of the woody flora and vegetation of Xinjiang were analyzed. The main conclusion is as follows:(1)There are 436 species (belonging to 37 families and 105 genera) of the woody flora of Xinjiang. Among them, 22 species belonging to 3 families and 6 genera are the gymnospermous flora, and 414 species belonging to 34 families and 99 genera are the angiospermous flora. (2) From the point of nature geographical region view, Xinjiang consists of several parts, e.g.Mt. Tianshan, Mt.Altai, Tarim Basin, Zhungeer Basin, and Xinjiang Desert Region. They are different from each other in the floristic properties, for example, Mt.Tianshan is characterized by the dominant Tianshan elements and abundant Europe Siberia Tianshan one;Mt.Altai is characterized by the dominant Siberia Altai one and Europe Siberia one; Tarim by dominant Center Asia one; Zhungeer by dominant Center Asia desert one, and Xinjiang Desert Region by Tethys Center Asia one which is related with Tethys flora. (3) The floristic composition of the woody flora of Xinjiang is very complicated. Their origin is pluralistic, and the origin geological periods are also different among nature regions. As for the original elements,they mainly include Angola, Old North Pole, Tethys and Cathaysian floristic elements. In the north of Tianshan,especial in Altai and Zhungeer, they maybe derive from the Angola and the Old North Pole elements. In the sorth of Tianshan,especially in Tarim Basin,there existe the dominant desert elements come from Center Asia; in the desert region of north Xinjiang,especially in Zhungeer Basin, Old Tethy and Center Asia elements are abundant.The desert flora in Xinjiang is more antique than the mountain flora. The former could derive from the early Tertiary; the desert flora in Zhungeer Basin could form in Quaternary, the latter could also form in Quaternary.Although some of Xinjiang mountains had risen free after Old Tethys gone away,they were affected deeply by glacier,and the present flora has been controlled continuously by arid climate since Tertiary period,and it became more and more dry in Quaternary.