Environmental condition and rapid trace of climate change in decades caused huge problems. Destructive flood as a phenomenon caused irreparable damages to different parts of our country. Different kinds of modelling system have been suggested to estimate flood in the world. These models in comparison to each other are relatively better with some positive points. In this study based on Schneider formula and SCS model, GIS equipment’s software and programing; a highly graphical software has been designed in which GIS library and high speed calculation of basin’s physical parameters provided in order to estimate the unit hydrograph without statistical data series. Also having compared SCS model and Schneider; we could represent better model to estimate flood hydrograph. This innovation caused decreasing the time and the cost of investigation of flood hydrograph in different times of precipitation and the amount of precipitation and varied condition in Golpayegan watershed. The result showed that by considering R; occurred flood on 1392 had a lower linear correlation (determination factor: 0.2 – 0.54) that the main reason is implementing dikes in different riches which was not considered in calculation. Occurred flood on 1386 and 1388 had a better correlation (determination factor: 0.6 – 0.7). It is needed to mention that by increasing time of raining this trace gets better for 1392 that the most significant factor is increasing base time of hydrograph especially in Schneider hydrograph while two main flood on 1386 and 1388 had stable trace and are compatible with our output in the software. These outputs from SCS were close to Schneider (in 1392 0.2-0.53, in1388 and 1386 0.7/0.85). By considering this results; SCS hydrograph shows a better estimation. Keywords : flood, rainfall, prediction software, synthetic unit hydrograph, Schneider, GIS, Arc Engine,
