On the basis of calculation of light-temperature potential productivity being modified by natural factors such as rainfall, soil fertility and soil quality etc, the potentials of land productivity and food productivity in Yuling Municipality are analyzed. Furthermore, the maximum grain yield and population supporting capacities in Yuling in the years of 2005 and 2015 by means of AEZ (Agriculture Ecology Zone) method. The key factors for realizing a harmonized and sustainable development relationship between human beings and land resources are also pointed out.