Based on the field investigation,some specimens and data of relative information,a catalog of wild seed plant,and the floristic of wild seed plant analyzed.The results show that:(1)There are 770 species in 261 genera and 60 families of wild seed plant in the Big Youerdosi Basin of Bayanbulak.(2)11 dominant families are Gramineae,Compositae,Leguminosae,Caryophyllaceae,Rosaceae,Brassicaceae,Cyperaceae,Ranunculaceae etc and Leguminosae,Gentianaceae,Caryophyllaceae,Gramineae are regarded as the typical families.(3)The temperate distribution occupies the overwhelming superiority.In a the Family level,temperate-type belongs to 30 families,accounting for the total number of subjects(excluding the world wide families) of 88.24%.In a grade level,the temperate distribution patterns of the 200 genera,is the total number of 97.78%.At the same time,some plant species are the most interflows between in this area and the Mediterranean,Central Asia,West Asia,little communication with East Asia and tropical.(4)There were no genera endemic to China in the area,although 55 species were China specific in the area,which 32 species endemic to Xinjiang in the area.