Determined the soil moisture dynamic and evapotranspiriation of Caragana microphylla plantations with different ages during growth period in field condition. Result showed: there are distinctly differences on soil moisture and evapotranspiriation between plantations with different ages. Moisture of soil under artificial plantations is continual decreasing along with the increasing of ages. The moisture contents of 16 and 19 years old shrubs decreased along with the depths of soil. There is a low moisture contents lay in 70cm depths of soil. The soil under these plantations gradually translated from leached soil to anti-leached soil. Precipitation and vegetations effected soil moisture contents during growth period, and soil moisture contents appeared lowest point in June. Evapotranspiriation is continual increasing along with the plantations ages increasing and the 19 years old shrubs had the maximal evapotranspiriation. During growth phases, quantities of evapotranspiriation of all plantations are low than rainfall and occupied above 95% of rainfall at the same time. The floating dunes are different from fixation dunes. Soil moisture under floating dunes are high and quantities of evapotranspiriation are low than shrubs area.