The frozen soil region of many years located in the Qinghai-Tibet Plain hinterland, Changing of the Water content of soil during freeze-thaw process, intensely responds to climate change and brings remarkable change on land energy-water balance, then has the large feedback function to the global climate. In order to reveal this kind of change, we used the observation data from the wind volcano testing field system, selected water-heat coupling model SHAW as dynamics restraint frame, which consider the influence of snow cover & the vegetation cover & the forest flooring to the soil freezing and thawing, and improved SHAW forecast capacity to the soil moisture content and the frozen soil depth by Ensemble Kalman Filter of data simulation method. The analysis based on data assimilation theory indicate that the data assimilation method may remarkably enhance the forecasting ability of water-heat coupling model to state variables, and provide theory basis for monitor utilizing multiple source information in frozen soil area.