Abstract: 【OBJECTIVE】To study the antioxidant activity of the protein hydrolysates prepared from bee collected rape pollen, and to investigate the mechanism of those effective compounds to scavenge superoxide anion radicals.【METHOD】Protein hydrolysates were made from bee collected rape pollen by enzymatic treatment using an alkaline protease. Ultrafiltration was applied to separate protein hydrolysates into five fractions based on the molecular weights. The antioxidant activity of the proteins hydrolysates was evaluated by their abilities to scavenge superoxide anion radical produced by the action of xanthine oxidase on xanthine. 【RESULTS】Significant radical scavenging capacity was demonstrated by the fractions with molecular weight higher than 1000. 【CONCLUSION】 Protein enzymatic hydrolysis and membrane filtration was found effective method to concentrate the functional compounds with antioxidant ability