After being activated by epoxy groups, Sepharose 4FF was grafted with dextran and then epoxy-activated followed by being coupled with alkali-resistant protein A ligand. In this paper, the cleaning-in-place performance of the medium is measured, and thermodynamic studies were carried out. Compared with non-grafted medium, the maximum velocity of dextran-grafted protein A medium was increased by about 32%. The binding capacity of antibody hIgG of dextran-grafted protein A medium was 60.6 mg/mL, which has reached 123% and 95% of the values for non-grafted protein A and MabSelect SuRe. After 40 cleaning-in-place cycles rinsed, the dynamic binding capacity of dextran-grafted protein A maintained the original capacity of 92%, which was almost the same as MabSelect SuRe and was also much higher than non-grafted Protein A. The capacity of non-grafted protein A maintained the original capacity of 84%. Thermodynamic studies showed that the binding processes of three chromatographic media were entropy-driven processes. The adsorption heat of dextran-grafted protein A medium was between that of MabSelect SuRe and non-grafted protein A.