Abstract: Hebei Province is a region where high water demand and low water resources self-yield are extremely unmatched in China and even in the world. With the rapid economic development, it is particularly significant to optimize the allocation of regional water resources scientifically. In this study, Hejian County, located in Cangzhou, Hebei Province, was selected as the study area. Considering the constraint effect of two forbidden red lines of water use amount and water use efficiency, an optimal allocation model of water resources taking social and economic benefits as objective function was established. Then Artificial Fish Swarm Algorithm was employed to solve the model. The results indicate that the available water supply would be 107.28 million m³ in Hejian County and the water shortage rate would be as high as 50.8% in Longhuadian Town, and the water scarcity in each township would be mainly concentrated in agriculture in the planning year of 2025. The water use contradiction in various industries would be obviously improved after the optimal allocation of water resources. The achievements can provide key technical support for the fine management of water resources in Hejian County, and can also provide a reference for other counties in the north to optimize the allocation of water resources.