To retrieve the spatial distribution of bare surface’s soil moisture at a large scale accurately and instantly，based on a commercial satellite named RADARSAT2, the authors studied the technique and method of soil moisture retrieving. An irrigation zone of Hetao Plain, located in Shanba town, Hanggin county, Bayannur city, was taken as an example for soil moisture with fourpolarized radar refined monitoring. According to advanced integral equation model(AIEM), an empirical model of bare soil moisture with microwave scattering was established , which was suitable for Hetao irrigation area. The empirical model of surface water inversion in Hetao irrigation area was applied , and it was compared with the measured data through correlation analysis. The results indicate that relevant coefficient of polarization combination VVVH is as high as 0.9311. The model can meet the requirements of soil moisture monitoring, superior to traditional soil moisture classification methods. Finally, it promotes the application of polarized microwave remote sensing in soil moisture monitoring.