With increasing growth of urban population and urban development, the necessity of building new public service centers and determining an optimal place for them have become obvious. Due to dramatic increase in population, chaotic development of the city, and increase in the number of vehicles manufactured in the metropolis, Tehran faces a shortage of appropriate places for parking vehicles in crowded areas. Optimal locating of public parking lots is an approach and solution for traffic dilemma. Geographic information systems and Boolean logic are appropriate systems for finding the most optimal place for building Multi-story parking lots. This article investigates and evaluates multi-story parking lots in Tehran 15^th district, considering parameters like attractive centers for travelers, access networks and urban passages, quality-structure, traffic junctions, different useful land uses, etc. Analytic hierarchy process (AHP) was used to weight the above mentioned parameters, and Boolean logic was used to overlap produced layers. After applying final weights retrieved from AHP model and overlapping produced layers, optimal sites for locating Multi-story parking lots were determined. Finally, suggestions were proposed according to the results and requirements of time and space.