A diagnose model is concluded from the synoptic and dynamical model of affecting Liaoning Province precipitation, and some synthesis physical factors are constr ucted. Based on the climate features of precipitation, the partially distributin g precipitation is normalized to satisfy the needs of building steady equations. The precipitation is divided into two sorts (rain, no-rain), and then rain sam p les are normalized with the method of classification and extraction of 4 roots. The precipitation forecasting model, which includes rain probability and precipi tation models, is built with the statistic method. The results of operational ex periments in 2000 show that this model has great capabilities in forecasting rai ns, and the precipitation-normalized model is better than the non-normalized.