The present study was conducted to assess the extent of flooding potential in Gorgancity with 3652.85 Hectares based on hydraulic, vulnerability and environmental effects criteria’s using multi-criteria decision techniques and geographical information system.For performing the program, firstly the entrance vector layers including urban land use, floodways, channels, digital elevation layers, geology layer and groundwater level layer were imported to GIS environment software and then these layers were converted to raster format after the desired post-processing courses in study area context. In the next step, hierarchical structure was formed regarding to problem goal and then the weighted index of each information layers and their various class were surveyed based on weighted index AHP using Expert Choice software. The final potential flood map was classified based on accumulative curve of pixels frequency millstone in five classes of very low, low, moderate much and very much according to multi-criteria decision-making rules after weighting on each principle layers (vulnerability, hydraulic and environmental effects).So that 1.7% of the study area occurred in risk class 1, 11.6% occurred in class 2, 43.07% occurred in class 3, 24.3% occurred in class 4, and 19.1% occurred in class 5.