By using the real-time and historical datasets of the quantitative forecast data from National Meteorological Center of CMA and automatic soil moisture monitoring data, the daily rolling forecast of soil moisture in the next seven days in Liaoning province was researched with the theory of soil water balance principle. Results demonstrate that the forecast model is stable, and can better simulate the quantitative evolution trend of soil moisture. The quantitative forecast, fine forecast, daily rolling forecast on soil moisture are realized firstly by this model. The key to the successful implementation of this method is the realization of the conversion between the meteorological forecast elements supplied by observation and the elements used in the model based on the regression analysis method.