On the base of grid point data from T213,HLFS,MM5,and Japanese model,a Shanxi Province precipitation diagnosis model is induced. According to the precipitation forecast function and its good/bad characteristics of every kind of numerical model and the reality that in the numerical model the prognosis is superior to the elemental prediction,the operational automatic flow of the area rainfall is made to start different predictive equations under the background of different synoptic situation,which can effectively overcome the weak point that the forecast output can not quickly respond to the circulation patterns when these patterns are adjusted and can improve the forecast accuracy of the area rainfall.