Despite the significant role of wetlands in maintaining a healthy ecosystem and providing various ecosystem services, they are under threat due to human activities and agriculture use. The fact that the economic value of ecosystem services is not considered in hydro-economic models and integrated water resources management is a key issue that affects the ecosystem and its degradation. the economic value of ecosystem services provides a quantitative and important basis for the reasonable management of water resources. Given that supplying the agriculture and environmental demands conflict with each other, achieving a balance between these goals is very important. So, in this study, a simulation-optimization (WEAP-PSO) approach is employed for optimal planning at the basin and designing environmental flow based on wetland ecosystem services. The objective function of the problem is considered to be the total economic value of the river, which includes the economic value of the agricultural sector and the economic value of the wetland ecosystem services. The decision variables of the problem are considered as, the cultivation area of agricultural units and environmental flow of Kani Barazan wetland. The results show that considering these two objectives together, in addition to sustainable development, causes the highest economic efficiency in the basin.