The change in the land use due to urbanization 1.11 times in 10-yr. this result, indicated, urbanization leading to a decrease of infiltration potential and increase of peak flow discharges and flood volumes and small floods were more sensitive than large floods to urbanization. Also, total of flood damages by 6 flood events in the past 50 years, estimated 715,500,000 tomans. According to this results and The require to create new green space and water shortage problems should be provide an approach of flood mamangment such as methods of runoff harvesting in other to irrigation of urban green spaces.leads to growing problems in urban hydrology and these increases peak flow discharges and flood volumes. Region 22 is one of the largest urban areas of Tehran, This area is located adjacent two catchment, Kan and Vardij. Rapid urbanization leading to higher flood risks in this area. In this paper, Firstly, The required information were prepared using GIS and Landsat satellite image and then peak flow discharges was estimated by three methods, including statistical distribution, SCS and Rational method. Also in order to estimate of flood damages, were taken data of Flood event, in the past 50 years and then damages of this phenomenon were estimated using questionnaire in today's prices.comparison of results from peak flow discharges,in Kan catchment and urban basin (region 22) in 2-yr period showed, increasing 6.2 times of peak flow discharges in urban basin than Kan catchment. this proportion was reduced 1.55 times in 5-yr and