The site selection for the construction of the power plant during construction and operation phase plays a key role in determining the relevant costs, plant efficiency and the impact on the environment. So before power plant construction, it seems to be necessary to conduct a thorough review of the location of the study area, to avoid financial losses, technical, environmental, safety and maximizing power plant efficiency. In this study, we used multi-criteria analysis (MCDM) methods in GIS software to site selection the power plant in Kahnooj. in this study the Criteria for the establishment of the Power plant used included of: elevation, slope, distance from surface water, distance from ground water depth, distance from roads, distance from the city, land use and distance from the fault. For land-use mapping, was used landsat satellite imagery in 2013. Kappa coefficient is 91% and an overall accuracy is 93% was achieved for the map. Other maps were prepared for the existing data. Groundwater or surface water, groundwater Piezometric depth map of the distribution of the IDW interpolation method was developed wells in the area. Standardization of criteria was done in two ways: Boolean and fuzzy. Weighting parameters were calculated through Analytic Hierarchy Process (AHP). The criteria for combining the three methods Boolean, fuzzy weighted linear combinations were used.The results of the combined maps by Boolean method were 5 spots. Due to their small area, only one spot with an area with ??151 hectares were suitable for power plant establishment. Combining fuzzy logic method shows two spots with area of 210 and 177 hectares were acquired, smaller spots because of the close to infrastructure and share with the fuzzy spots, were selected. The weighted linear combination method to produce a final map that maps the criteria of suitability criteria into the weight of each factor was multiplied and then combined. This model is due to the weighting of each map, flexible and more accurate than other models. Keywords: Multi-Criteria Decision Making Analysis, Analysis Hierarchy Process, GIS, Boolean logic, Fuzzy logic, Site Selection, Power Plant.