Abstract: The duration of freezing and thawing period almost accounts for a half year in the inland basin of northwestern China,in which the characteristics of soil moisture transfer is greatly differential from that of non-freezing period.Based on the observatory experiment on soil moisture transfer in inland plains,the distribution of soil moisture potential and the regularity of soil moisture ratio variation as well as its converting to groundwater during freezing and thawing period are analyzed.The significance of thawed water in eco-environment is also expounded.