Abstract: The paper aims to study the effect of precipitation of summer fallow period (July-September) in Fushan on winter wheat production next year, make a forecast for wheat yield, and put forward the countermeasures to guide wheat production while avoiding disadvantages. By analyzing the precipitation of summer fallow period (July-September) and winter wheat production next year during 1980-2009 in Fushan, Shanxi Province, the authors used the SPSS software to separate the trend yield and meteorological yield, and established the regression equation of wheat yield. Through the analysis of meteorological yield and precipitation of summer fallow period, the logarithmic equation of the two was established and the wheat yield forecast model: Y = 2.995T 68.102lnX-254.578 was set up. The results showed that: the fitting rate of precipitation of summer fallow period (July-September) and winter wheat production next year in Fushan was high, the highest prediction accuracy was 99%, and the average prediction accuracy was 80%. In conclusion, the precipitation of summer fallow period (July-September) in Fushan county and winter wheat yield next year had significant correlation, the forecasting accuracy was high; but without the consideration of the precipitation impact on winter wheat in the growth period, in case of large-scale and serious natural disasters, the forecast accuracy might be greatly reduced.