Mesoporous Fe2O3 nanoparticles were synthesized by a gas-liquid chemical precipitation method. The thermodynamics and the kinetics of Fe2O3 adsorption on Congo red (CR) were studied by the set of equilibrium experiment. The results showed the adsorption isotherms were modeled by Langmuir model, and the parameters indicated that the adsorption was strongly dependent on temperature and the adsorption of CR increased with increasing temperature of the system. The calculated parameters indicated the adsorption process was determined as an endothelium process and a spontaneous process. Furthermore, the adsorption process reached equilibrium in 6 hours, and the kinetics adsorption of CR can be described by pseudo-second-order rate very well.