This study consists in evaluating activated carbon was prepared from agricultural waste: date stones, for the decolorization of water contaminated by Malachite Green and Brilliant Green used in the activated state by studying the adsorption capacity of these dyes. After determining the effect of various factors influencing adsorption, such as pH, initial concentration and quantity of activated carbon, a kinetic and isotherm study of the adsorption was carried out. At the end of this study, it was established that the experimental results of adsorption of dyes on activated carbon are well represented by the pseudo-second order model, Langmuir model and the Freundlich model.