The ERS-1/2（European Remote-Sensing Satellites-1/2） wind scatterometer（WSC） has a resolution cell of 50 Km

but it covers more than 80% of the Earth surface in four days and can make measurements at multiple incidence angles.In this paper

the method to estimate soil moisture is studied using WSC data.Firstly

based on classical GOM model

the high correlation between WSC data and soil moisture is proved

by comparing in-situ-based precipitation and soil moisture with derived Fresnel reflectivity at normal incidence（which is very closely related to soil moisture） at two points（Amdo and Naqu）.This part of work is performed using Database of Global C-Band Radarbackscatter

which is derived from original WSC measurements.Secondly

a simplified algorithm is proposed to estimate soil moisture based on "Water-Cloud" model and AIEM model

the validation is performed using both in-situ-based soil moisture and Basist Wetness Index（BWI）

showing that the algorithm can estimate Spatio-temporal soil moisture distribution effectively.