Abstract: Counteracting chromatgraphic electrophoresis (CAGE), a preparative separation device is successfully constructed and tested. Experiments are performed with protein mixtures of BSA, Hg, Mg and Cyto - c to study the separation performances, concentration profiles, start -up ways as well as influences of pH and ionic strength on separation process. Mathematical models are proposed based on the fluid dynamics of porous media. Results indicate that the CACE process has a good potential in protein and fine chemicals purification.