Wuqi County is a major county to implement the grain for forest and grass(GFG) project in China,with the percentage of the GFG area reaching as much as 38.3%.So,how to sufficiently guarantee the amount of grain production and continue practicing the GFG is extensively concerned by people.The study is based on the statistical data of Wuqi County from 1999 to 2005.The GFG project affects the relationship between the volume of grain output and demands.It is believed that the GFG project can keep on performing.On the assumption that all conditions are same in the future years,predicting models of total output,population,unit area output,and grain consumption per capita are constructed by using grey predicting method GM(1,1).Using these models,the suitable area for the GFG project from 2008 to 2012 is calculated,which provides a scientific basis for the development of Wuqi County.