Rivers as a blue ecosystem have a lot of ecosystem services that awareness of the value of their services will protect them as much as possible and communities will benefit from their environmental services. In this study, Tajan river basin ecosystem services in the north of Iran was valuated. To valuate, the choice experiment method was used to estimate willingness to pay. Tajan river basin ecosystem services attributes including regulating, supporting, provisioning and cultural services and a price attribute at three levels were determined. Data from 239 resident households of Mazandaran province were used in 2017. The empirical analysis did by the conditional logit model and mixed logit model. Also, multi criteria decision making including techniques Entropy, TOPSIS and SAW used for evaluating the role and importance of the Tajan river basin ecosystem services. The findings indicated that residents were willing to pay for the conservation of Tajan river basin ecosystem services, 13.77 USD per year. It was for regulating, supporting, provisioning and cultural services of Tajan river basin, 2.62, 6.30, 2.50 and 2.35 USD per year to move away from the status quo to the improvement status respectively. Also, findings of weighting and prioritization of Tajan river basin ecosystem services with TOPSIS and SAW methods showed that supporting and provisioning services had the highest weight for the evaluation Tajan river basin ecosystem services. In other words, the residents prefer the services as the most important Tajan river basin ecosystem services. Results showed that willingness to pay can be introduced as a useful tool to investigated people's preference for conservation of river basin ecosystem services under various activities. Therefore, by determining the value of river ecosystem services, community will understand that river services are of great importance, and the application of its value in calculations related to comprehensive management of basin water resources will provide a suitable economic solution to increase user utility the river.