The Sebou watershed is the main receiver of rainwater contributions in the North of Morocco. The present study is interested in the knowledge of the global Physical characteristics on water dynamics in the Sefrou watershed at the level of the Sefrou sub-watershed which belongs to this large hydrological unit and which occupies its south-western part. The approach followed in this study consisted initially, in acquiring the data, organizing it, and processing it by a geographic information system (GIS), in order to obtain a global idea on the distribution of the different parameters in the entourage concerned by this study. The application of geographic information system tools makes it possible to establish a set of maps that will help develop an excellent descriptive analysis characteristic of the watershed. In this paper, we present the analysis results of the geological, climatic and hydrological characteristics of an important area of the Middle Atlas, with the notable importance of precipitation, runoff and rivers for irrigation and the supply of drinking water. of cities in the region. The hydrological study of the Sefrou watershed has shown a typical Mediterranean regime, the watershed receives an average annual rainfall of 454.22 mm, with a volume input of 183,96*10 ^6 ^3/year and an average annual temperature of 16.62°C. The actual evapotranspiration in the watershed is 389.22 mm/year which is 161,28.10^6 m^3/year.