Aimed at the Hanjiang River, the theoretical system for the study of water ecological carrying capacity in the Hanjiang River is established through a combination of the water ecological carrying capacity with the ecological environment water demand and water environmental capacity. On the basis of the water resources, water quality and aquatic biomass in the basin, the Hanjiang River ecological carrying capacity index system is established, and the system dynamics model is used to construct the system dynamics model of Hanjiang water resources-environment-society-economic-water ecological coupling. The calculation results show that the Hanjiang River is in a weakly loadable state under the current development situation. With the application of five adjustment strategies for quantitative control, the results show that each program can achieve a certain increase in water ecological carrying capacity, but the overall trend is still declining, and there is every need to moderately adjust the speed of economic development and population growth rate, in the meantime, save water, control pollution and increase investment in environmental protection.