The conversion from farmland to forest or grassland is an effective way to make North-west China beautiful,but necessarily it may influence the grain production of that region.Accord-ing to the plan made by the five provinces /municipalities,till2010the accumulative total area of farmland to be converted to forest or grassland is about 400×10 4 ha,or24.8%of the total farmland area.That is to say,400×10 4 t grain(12.4%of the total grain production in1996)will be minified in Northwest China.Simultaneously positive impacts caused by this kind of conver-sion must be seen.They are expatiated as below:(1)the transfer of water,fertilizer etc.to re-served farmland can bring more marginal profit;and(2)the improvement of ecological condi tion and local environment can promote grain production and reduce the risk of natural disasters.Furthermore,the advancement in agricultural science and technology,and the construction of a-gricultural infrastructure must make reserved farmland more productive.After predicting we can see that the total yield of grain in Northwest China will hit4516.9×10 4 t,and the demand of grain,respectively based on the different level-400kg,425kg or450kg per capita,is about 3936.1×10 4 t,4182.1×10 4 t or4428.1×10 4 t.Then a conclusion can be drawn that from the long-term point of view the grain shortage will not appear in Northwest China on the whole,but the situation is austere.To achieve the equilibrium of demand and supply,Shaanxi,Gansu and Qing-hai must import grain from Xinjiang and Ningxia.