Taking the territory of Hohhot City as the study area, and based on dissipation structure theory and the principle and method of system dynamics, a model of regional population carrying capacity of land resources was developed. The results of the simulation show that the medium scheme is the optimal one, then by 2020 the area of farm land will have been reached to 52.42?10⁴ ha, the area of grassland 61.86?10⁴ ha, the percentage of forest cover 35.04%, the value of GDP at 2789.01?10⁸ yuan (RMB), the population 372.34?10⁴, and all the indexes showed above are between the range of high scheme and low one. From the food-population carrying capacity, the result is low scheme> mudiem scheme>high scheme; from the currency-population carrying capacity, the result is high scheme> mudiem scheme>low scheme; from the population comprehensive carrying capacity, the result is high scheme> mudiem scheme>low scheme. The food-population carrying capacity, currency-population carrying capacity and population comprehensive carrying capacity will be 3.1?10⁶ person, 17.32?10⁶ person and 10?10⁶ person respectively in 2020, which indicate that the contribution of the currency-population carrying capacity to the population comprehensive carrying capacity will exceed that of the food population carrying capacity greatly. The suggestions are taken seriously in development and protection of resources and environment while developing the economy, intensifying the rebuilding of the environment, harmonizing the relationship between the economic development and the environment, making up the insufficiency of food population carrying capacity by developing the economy, improving the population comprehensive carrying capacity and promoting social and economic sustainable development.