Abstract: Chitosan modified montmorillonite was prepared by coprecipitation method and used to adsorb phenolic acids in sucrose solution. It was characterized by SEM, FT-IR, XPS and BET. The results showed that chitosan was successfully loaded on the surface of montmorillonite to prepare chitosan modified montmorillonite. The isoelectric point of modified montmorillonite was 7.84, and gallic acid in sucrose solution was mainly adsorbed by electrostatic force and amine group. The results of adsorption test showed that the modified montmorillonite had better adsorption performance for gallic acid. The optimal pH of chitosan modified montmorillonite for gallic acid adsorption in sucrose solution was 7.0, and the equilibrium time was 600 min. The adsorption process of chitosan modified montmorillonite for gallic acid was more in line with Freundlich model and quasi second order adsorption kinetic equation. The adsorption process was mainly multimolecular layer adsorption and chemical adsorption, and the saturated adsorption capacity reached 58.82 mg/g. Chitosan modified montmorillonite exhibited a good regeneration performance and good adsorption effect on phenolic acids in sucrose solution. It performed a promising clarifier for sugar.