Abstract: Seven protease producing strains were screened from fermented food by using hydrolysis circle screening model,respectively which were named strain A,B,C,D,E,F and G.Potato protein was fermented by the protease producing strains,the degree of hydrolysis and the antioxidant capacity of potato protein fermentation products were investigated. The antioxidant activities of the fermentation products were measured by the scavenging ability of 1,1-diphenyl-2-pycrylhydrazyl( DPPH). The results indicated that seven strains fermented product of the DPPH radical scavenging rates were respectively: 88.32%,92.00%,24.49%,76.90%,53.02%,18.11%,55.69%.Strain B had the higest antioxidant capacity.