Agriculture is the fundamental industry to national economic and social development

and it provides the necessary basic material to national economic and social development.A farm productivity prediction method based on the NGM(1

1

) model was proposed in this work.The disadvantage of original NGM(1

1

) was analyzed

and an improved NGM(1

1

) was proposed based on the grey forecasting model of Nonhomogeneous index series.The differential equation model meets the unbiased of forecasting model.The experimental results suggest that this new NGM(1

1

) is feasible

correct and valid.