The paper analyzed the ecological cost and direct cost of grain production in the Guanzhong-Tianshui Economic Zone using the principal component analysis based on the theories of ecology

economics and water and soil conservation combined with remote sensing image.The results demonstrated that the ecological cost of grain production reached to 0.8yuan/kg

direct cost of production was about 1.45yuan/kg

which led the total cost of 2.25yuan/kg close to the sale price of 2.56yuan/kg in Guanzhong-Tianshui area.Soil erosion was an important factor affecting the ecological cost of food production and high seed price and machinery expense are the key factors that caused high food production cost.The situation of high cost and low income would significantly discourage farmers engaging in the food production therefore it is important to make full use of agricultural resources

increase investment in agricultural science and technology and expand the farming scale in order that the unit ecological cost of food production be reduced.