Abstract: Since the summer rainfall abnormality has close relationship with both the soil moisture and temperature abnormality. We study the impact of pre-wintertime and springtime soil moisture and temperature on the summer rainfall over Huaihe river basin. In this paper, we present a blending method of dynamical and statistical approach to choose the attributing factors that may effect the precipitation.The approach has established a relationship between monthly precipitation abnormality and monthly circulation, soil moisture and temperature on the shallow and deep layers. The relationship is the precipitation diagnostic equation and its coefficients and dimensions are determined by using the observed data of Huaihe river basin. Then we select the mainly soil moisture and temperature attributing factors by the dimensional analysis to establish a forecasting equation of summer precipitation over Huaihe river basin with the statistic approach. The results indicate that those soil factors, which are selected by the blending method of dynamical and statistical approaches, are useful for forecasting monthly summer precipitation and can expressly discover their dynamical relationships. 