Abstract: Through the analysis of soil moisture content at all levels in different periods of Hulunbeier western grassland,The soil drought characteristics of the semiarid grassland is revealed,The seasonal distribution of drought and characteristics of moisture in the soil levels are analysed monthly.The results showed： Particularly drought appeared often in 20cmdepth,moderate and light drought appeared often in 50cmor 100cm depth,serious drought occured with low frequency at all levels,the frequency of drought was more than 55%;The characteristics of seasonal distribution of drought expressed：Drought began to develop in spring,reached the most serious in early summer and rose again slightly in autumn,but is not to be able to restore soil moisture levels in early spring before the frozen,soil layer remains drought status, heralding spring drought may occur in the coming year;The western grasslands in Hulunbeier continuous drought in the spring,summer,autumn and three quarter reflects significantly.the climate characteristics of semi- drought ~rasslands.