Abstract: In the objective to rehabilitate the degradation soils and improve the agricultural product, especially cereals and leguminous plants, in the sandy soils countries, we take an interest in the use of bentonite to ameliorate the physical and chemicals properties of these soils. To value the ecological advantage of this clay in these countries, it is proposed a study of increasing amount effect of bentonite on the physical and chemical characteristics on sandy soils. Results show that the texture of mixture tends from sandy soil under 2.5% of bentonite added to sandy silt soil under 7, 10 and 15% of bentonite. The EC increases with the amount bentonite mixture. pH does not fluctuate from one mixture to the another and tends to the alkalinity of soil; Total CaCO3 raises when the bentonite is added in the mixture but active CaCO3 decreases. The high bentonite amounts (10 and 15%) showed no effect on the total phosphorus. The mixture bentonite at 15% reduces the organic carbon and organic matter, whereas total nitrogen falls down when this mixture is enriched with bentonite. Na+ and Ca++ become higher when bentonite increases its amount; K+ reduces in all treatments then this reduction affects Mg++ only under high mixture bentonite (15%).