In past times, castle settlements as one of the centers of human collective life was affected by various environmental-natural variables such as climate, elevation, distance from the river, land form, slope, aspect, soil type and vegetation. In this regard, the present study is based on field and documentary data and using ARAS model and GIS, seeks to model the relationship between environmental-natural variables with the spatial distribution of castle settlements of east Azerbaijan province. Based on obtained date from field and documentary studies, 100 castle settlements from different prehistoric, historic and Islamic periods in the geographical area of East Azerbaijan province were identified and evaluated, which are forming materials and statistical society of this research. to analyze the data, after forming the database, spatial distribution of the identified castle settlements were evaluated and analyzed in relation to the variables of climatic classes, elevation levels, land use/vegetation, soil type, slope, aspect, distance from the river and land form. Findings of these data analysis in the form of ARAS model show that distance from the river, land form (plain and mountain) and elevation levels have the most effect on the spatial distribution pattern of these settlements. Other natural variables such as climatic classes, slope, soil type, land use/ vegetation and aspect have been effective in the spatial distribution of these settlements in terms of importance and impact, respectively.