Abstract: Currently, there are two dominant methods, Model Output Statitics (MOS) and Perfect Prediction Method (PPM), in reexplanation and reanalysis of dynamic products based on potential height of model outputs. The forecast equations which are estabalished by using these two methods have statistical meanings except physical senses. In this paper, we present a blending method of dynamical and statistical approaches, which has est ablished a relationship between monthly precipitation anomaly and monthly circulation. The relationship is monthly precipitation fo recast equation and its coefficients are determined by using 500 hPa potential height anomaly of ensemble dynamical extended range forecast (DERF) and observed precipitation. The results show that the method is useful for forecasting monthly rainfall anomaly using potential height of ensemble DERF through independent sample tests.