Floods are one of the most common natural hazards in the world, causing a lot of damage and loss of life every year. In Algeria, many events have caused serious damage over several decades, recorded at the national level; among them, the flood of Mohammedia 1881, Mostaganem 1927, Oued R’hiou 1993 and Bab el Oued (Algiers) 2001. In northwestern of Algeria, the Wilaya of Sidi Bel Abbes, several floods are frequently recorded, with high to catastrophic levels, causing serious damage associated with significant loss of human life. In this work, we propose an approach to evaluate the rate of susceptibility to flooding of the territory of Sidi Bel Abbes by a geodecisional analysis under the GIS environment. A total of nine factors influencing flooding phenomena such as, distance to rivers, slope, streams density, altitude, flow accumulation, rainfall, soil type, geology and land use are integrated in the flood susceptibility calculation. Based on semi-quantitative statistical approach namely, Analytical Hierarchic Process (AHP), the weighting of each parameter is calculated. The Flood Susceptibility Global Index (FSGI) is evaluated using the weighted linear combination of the whole parameters used in this analysis. As a result, the flood susceptibility map is established by the classification of the envisaged index into five classes. The outcome of this analysis indicates that 41% of the study area characterized by very low susceptibility, 28% of the total area characterized by low susceptibility, 19% for the moderate flood susceptibility zones, 09% and 3% for the high and very high flood susceptibility areas, respectively. The establishment of the flood susceptibility map enabled us to understand the distribution of flood-prone areas and to better explain the preventive aspect of potential floods to local and/or regional communities in order to minimize the fatal effects of the hydrological risk.