The tourism industry is one of the important economic resources and today the countries of the world have studied it in different ways to estimate the potentials of their natural resources. Utilizing the potential and capabilities of tourism in any region spatially and temporally can provide a sustainable basis for the development of that region. Therefore, the purpose of this study was to establish a new and reliable procedure for studying ecotourism potential with different evaluation criteria and methods. In this study, with the method of intensive field study and questioning, first 37 ecotourism index points were identified, then by modeling different ecosystem services with the methods of decision system, the ecological potential of ecotourism in the basin was modeled. In this study, the aesthetic value of the landscape, the value of habitat quality and the rarity of the habitat from 2000 to 2020 were investigated. The results of this study showed that the ecosystem service criteria in the decision system with fuzzy gamma method improve the model from 0.42 to 0.766. Also, 8 common criteria in Makhdoom tourism model are not useful enough in ecotourism decision systems or can not be referred to other regions.