Using acrylic acid (AA) and chitosan (CTS) as raw materials and ascorbic acid (VC) as reducing agent instead of traditional amine reductant, the contunious ion exchange adsorption medium rich in -COOH group and -NH2 group was prepared by one step copolymerization. The polymerization time was shortened from 18 hours reported in literature to 5 hours. The optimum polymerization parameters were as follows: the total mass fraction of initiator was 0.75%. The mass ratio of VC to APS was 0.5, the total mass fraction of monomer was 7%, the mass ratio of CTS to AA was 0.2, and the mass fraction of cross-linking agent was 1.05%. The pore structure of p(AA-co-CTS) adsorption medium prepared was continuous and the pore size scale was 100~500μm. The abundant groups of -NH2 and -COOH on the inner surface of p(AA-co-CTS) adsorption medium had strong adsorption capacity for polypeptide. The relationship between mass transfer parameters and adsorption operation conditions was studied by number of mass transfer units (NTU) method. The optimum adsorption operation conditions were determined as follows: the flow rate of adsorption liquid was 3~4 mL?min-1, the adsorption temperature was 293.15K, the feed concentration was 400~500 mg?L-1, and the maximum dynamic adsorption capacity was 74.5~79.4 mg?g-1. The amphoteric separation medium has continuous pores and can be directly used to adsorb active polypeptides from enzymatic hydrolysate of marine fishery resources. It can replace the traditional adsorption unit operations such as filtration, centrifugation and bulk resin chromatography.