In recent years the increases in the popularity of applying environmental criteria in national planning and management has provided a wide range of scientific approaches to determine the best location of hazardous wastes to be land filled. In the present study, concern to the hydro-geological and socialeconomical considerations as well as national environmental legislations, an efficient method to determine suitable sites for land filling of hazardous wastes is presented. Site screening study based on GIS database in two scales, and priority processing are utilized. This approach demonstrates how the criteria such as geology, topography, land use, climate, surface and ground water chrematistics, accessibility, applicability and other related factors can be used into the over layer technique to determine some appropriate sites in a vast region. For priority processing between candidate sites also a new approach based on DRASTIC and MPCA methods and zonal feature of the study area is given. The introduced method was used to find a disposal site for hazardous wastes of Shahid Rajaee power plant in Qazvin province, located in west central part of Iran. Results showed that site named 1 in Abyeck zone next to Shahid Rajaee power plant has highest score between 17 primarily selected sites.