The Qaidam Basin and its contiguous region is situated in the northwest of Qinghai, China, between latitude 34°45′-37°00′N and longitude 98°45′-101°30′E. The study based on several field surveys in 1999, 2002 and 2006, and combined with more than 2 000 samples which the author collected from the QinghaiTibetan Plateau, and combined more than 10 000 previous specimens which had been collected from the Qaidam basin and its adjacent areas, identified by the plant taxonomist, then housed in the QinghaiTibetan Plateau biological specimens pavilion. The wild flora composition, properties, characteristics and the partition are analyzed. There are 854 species of native seed plants which belong to 62 families and 257 genera in the Qaidam Basin and its contiguous region. The floristic characteristics in native seed plants for the area are as follows: （1） species and woody ones are poor in the Qaidam Basin and its contiguous region. （2） On the level of genera, the flora distributed in the Qaidam Basin and its contiguous region which is dominated by North Temperate components especially the typical elements from the warm and cold zone of Eurasia, and have the temperate zone character of the drought temperature, cold temperature and alpine types. （3）Under the precondition of non Chinese endemic species, the flora of the Qaidam Basin and its contiguous region is dominated by Temperate Asia and Central Asia, with the distribution patterns of East Asia, the old world temperate and the north temperate. （4）In floristic geography, the Qaidam Basin and its contiguous region is a converged and transitional region for the QinghaiTibetan Plateau Alpine Flora, Loess Plateau Warm Flora, as well as East Asia Alpine Desert Flora, so the flora of the area is also conspicuously transitional one, so the edge character of the flora is obvious. （5） Due to the obvious difference of topography and hydrothermal conditions, the area can be divided into two parts: the main body of the Qaidam Basin which altitude above 3 500 meters and its contiguous region the altitude below 3500 meters. The latter is due to the high altitude and high mountain composition of the plateau, it is a part of the Tangute Flora. （6） It is the key area to divide the subregion in the flora of Qinghai on the Tangute Area. （7）The main area of the Qaidam Basin is relatively old and its contiguous region area is young.