This study is aimed to convert the real-time measured soil moisture into the soil water content which can be used directly in the watershed hydrological model, and demonstrate the feasibility of using the real-time measured soil moisture for real-time forecasting. In this paper, a rainfall-runoff hydrological forecasting model based on the measured soil moisture is proposed to improve the structure of the traditional model. The soil moisture robust estimation technique is used to resist the influence of gross error, and improve the stability of the system. On that basis, a soil water content error correction method based on a system response curve is introduced into the model to improve the accuracy of the model. The model is applied in an experimental basin named Baogaidong Basin. The result indicates that the qualification rate of basin flood simulation reaches 92.3%, and the overall simulation accuracy reaches Class A.