Abstract: A highly effective protein adsorbent was prepared using polysaccharide and metal ions. Sodium alginate and sodium carboxymethyl cellulose are two polysaccharides rich in hydroxyl and carboxyl groups, which have strong metal affinity. Both polysaccharides were cross-linked by calcium ions to prepare the metal-polysaccharide composite material, and further modified with copper ions to obtain the protein adsorbent. The adsorption capacity of the adsorbent for histidine-rich bovine hemoglobin reached 33 g/g, and for bovine serum albumin with a small amount of histidine reached 9.8 g/g. 98% of the protein in blood serum could be removed by the adsorbent after adsorption twice. The nucleoside substances in human serum can be analyzed directly by high performance liquid chromatography after the high-abundant protein is removed.