Due to the increasing population and the growing need for providing energy from a clean and non-fossil resource, there is an increasing interest in nuclear energy all over the world. As a fact, environmental capability evaluation should be considered for establishment of new nuclear power plants, not only to increase the safety against environmental risks, but also to achieve sustainable development. This study focuses on environmental capability evaluation for the nuclear power plant site selection in the coastal area of Gilan Province (Sahar Khiz). Considering the natural potentials and limitations of the area, the existing laws and regulations set by the International Atomic Energy Agency, United States Nuclear Regulatory Commission and Department of Environment, ecological and socioeconomic criteria were the main object of this study. At first, the Boolean logic method was used to prepare layered maps and identify selected zones, using geographical information system (GIS) and the ''AND'' operator. Then, the fuzzy logic method based on weighted linear combination (WLC) was applied for site selection of the new nuclear power plant. Four main criteria (physical, biological, social and economic) and 15 sub-criteria have been chosen for site selection process, from all selected criteria and sub-criteria. After preparing the raster maps of the ecological and socioeconomic sub-criteria, the fuzzy logic was used to standardize data layers between zero and one. Then, a relative weight was assigned to each criterion using Expert Choice software and the analytical hierarchy process (AHP) method. At the end, to combine all subcriteria, fuzzy logic method based on WLC was used in GIS environment, and the final map of environmental capability was prepared. The results of this study were compared to the results using the Boolean logic method, showing high coverage between the two methodologies, while the fuzzy logic method based on WLC combined with the AHP method had more flexibility and more accuracy comparing with the Boolean logic method.