Hydrographs are used in hydrological studies to illustrate the fluctuation of the stream during rainfall. A hydrograph's total flow includes runoff and base flow. The unit hydrograph only measures direct surface runoff. Modeling rain events by using unit hydrograph theory has the advantage of being easier to determine than hydraulic distributed modeling and can yield desirable outcomes for objectives of applied hydrology. The purpose of this research is to generate a unit hydrograph for a section of the Tazlău River Basin by utilizing the physical properties of its basin. For this purpose, parameters such as peak discharge, time to peak discharge and the base width of the unit hydrograph were determined. This research explored the use of GIS and Digital Elevation Model in the development of unit hydrograph for streamflow predictions and rainfall runoff modeling. The most common uses after creating a unit hydrograph are designing flood prediction, which estimates flood flows in real time based on rainfall records, runoff assessment from ungauged watersheds and supplement the incomplete archives.