Based on the performance of consolidation dewatering and supercritical carbon dioxide dewatering, the characteristics of supercritical carbon dioxide dewatering in soil were studied. In this experiment, the change of free water and bound water content in the soil before and after the experiment was studied by the treatment of carbon dioxide under different pressure and temperature conditions. The dehydration law of supercritical carbon dioxide in soil was studied. The experimental results showed that the moisture content of the kaolin treated by supercritical carbon dioxide decreased from 30.9% to 14.17% , and the bound water decreased from 20.06% to 8.46% . It is concluded that the dewatering effect on carbon dioxide in supercritical water is better than that under supercritical water, especially the removal effect of combined water better, that is to say, accelerating the consolidation and drainage of soil. The supercritical carbon dioxide for good dehydration effect with water, soil can also be used for high water content such as bentonite.