The issue of natural hazards in general and Floods in particular is a topic of current interest that marks a memorable action in the world and specifically in Tunisia, especially in view of the last major floods of the Medjerda. Indeed, the management of this risk becomes more and more a necessity that must include all actors and all possible means available. In this work, has been exposed the mapping of flood areas of the middle valley of the Medjerda by means of the combination of different complementary approaches of remote sensing coupled with GIS and hydraulic modeling (HEC RAS) and (HEC Geo RAS). The processing and interpretation of satellite images, has allowed to have a digital terrain model of high resolution, a mapping of land use at different dates and a hydromorphological map. Thus, simulations of three flood scenarios with three flows were made for different return periods. The combination of all these results allowed to elaborate the hazard map. This map seems to be one of the most effective means of efficient management.