The vertical hydraulic conductivity of unsaturated zone plays a very important role in the research of dynamic transport of water, root water uptake character and rule of surface water flow. This paper used inverse auger method to carry out the situ experiment of hydraulic conductivity of unsaturated zone in Maowusuo Desert. Data analyses indicate that:① in order to get vertical seepage conductivity, water should be supplied again so as to make unsaturated zone maintain moisture and diminish the effect of horizontal flow; ② when calculating vertical seepage coefficient by means of Porchet formula, statistics analysis tools can be used to discard err data of not in accordance with physics background. On the context of data analysis as mentioned, the vertical hydraulic conductivity of the experimental soil is 2.23cm/h. The analysis methods and the experimental results have certain significance for related experiment.