Abstract: In this paper, we have studied the adsorption of benzoic acid and anthracene from binary mixed solvents; on silica gel and activated carbon. The experimental results show that the adsorption of solutes from non-polar mixed solvents depends simply on their solubilities. However, when the adsorption of solutes from polar non-polar or polar-polar mixed solvents was dealt with, the situation is very complex. From constant boiling mixtures with a maximum (for example chloroform-acetone; 1, 2, 2-tetrachloroethane-cyclohexanone eto.),the, adsorption of anthracene varies with, the composition of mixed solvents, and a positive deviation from straight line is observed. From constant boiling mixtures with a minimum, the adsorption of solutes also varies with the composition of mixed solvents, but a negative deviation is observed. Based on the interaction between molecules in mixed solvents, the experimental results may be explained qualitatively.