The study area is located in the North of Morocco on the Mediterranean coastline. The purpose of this article is to know the principles of a study of soil stability using geological study and geotechnical test, in order to characterize and to undertake the stability of the areas subject of movement and particularly for landslides by a numerical method (SLIDE 5.0). It will also enable to define the nature of soil at the site using mechanical test and the pressumeter tests supplemented by laboratory tests to understand and deduce the risk of instability affecting this area. The studies and tests have allowed us to highlight a schistose soil. This schist are quite permeable, therefore the flow of water into soil, particularly clays and schist, and when it is saturated in water, its internal cohesion decreases very significantly, which causes the landslides. It is important to understand these instabilities in order to better characterize and define the kind of preventions for this area, where the subject of this study.