Nowadays, spatial spread balance in resources and utilities between cities is one of government aims. Utilities spreading balance is binded to their sites in order to all people can access them easily. On the other side, Land Surveying's main goal is regulating human activities in national environment to reach rational exploitation of resources and land capabilities. This goal could be accessed via GIS and its ability in various contexts. In this paper, we focused on spatial spread of Gas industry infrastructures, especially CNG stations in Qom province. First, we evaluated existing CNG cites. We designed special questionnaire containing questions about CNG station's quality, quantity, spatial and services. The forms were filled with drivers and we analyzed them. Also we used GIS to implement CNG cite standards and analyzed existing stations. Also we determined optimal places for CNG station using GIS. Our model includes AHP for weighting layers, a way that uses comparative methods for weighting, and Index Overlay for combining layers with AHP weights. Finally, we categorized Qom province in six categories ranging "Very Unsuitable Sites" to "Very Suitable Cites" for CNG station.