Public land-uses in many cities are not able to present desirable services to citizens because of some problems such as high population density, lack of regularity in establishment and site-selection, and lack of attention to accessibility radius and population thresholds. This problem is magnified in big cities especially for land-uses such as green spaces. In urban supplying services only increasing of services is not a reason for proper supplying services but more important is optimized distribution of these centers. In this regard, present paper based on descriptive-analytical method as well as GIS follows optimized distribution of green space in the cities according to site-selection principals of urban green space. Case study is region 7 of Ahvaz municipality which has a population of 150215 persons and 2.78 green space capita, and this amount in addition to significant difference to standards determined by environment united nations (20-25 for a person), has been not distributed optimally. Regarding this city locating warm and dry zone of the earth, it is very important to select an optimized site for green spaces .Hence, in order to select a proper and optimized site for the green spaces according to site-selection principals layers (criteria) such as vicinity to residential centers, educational centers, cultural centers, urban infrastructures and establishments, commercial centers, hygienic centers, industrial centers and wastelands and etc. have been used. Research results in fuzzy logic valued region lands based on their importance in recognizing optimized location. Afterward, these lands were compared with land-use map and it was distinguished that lands with very good, good, and medium degree were placed close to residential, cultural, and educational centers which had more governmental ownership, and lands with weak and very weak degree were placed far from compatible land-uses, and were more placed close to industrial, administrative, hygienic sportive, and commercial centers which often had private ownership, therefore, they were not suggested for creating green space.