Abstract: To study the degradation effect of alkaline protease on selenium-rich Pleurotus ostreatus and optimize its technological conditions.Using selenium-enriched Pleurotus ostreatus powder from Enshi as raw material,alkaline protease was selected to study the effects of ratio of material to liquid,amount of enzyme,temperature,pH and hydrolysis time on the hydrolysis of selenium-enriched Pleurotus ostreatus protein by alkaline protease.Taking the degree of hydrolysis and the dissolution rate of protein as evaluation indexes,the orthogonal experiment was carried out on the basis of single factor experiment to optimize the technological conditions of hydrolysis of selenium-rich Pleurotus ostreatus by alkaline protease. The results showed that the optimum conditions of enzymatic hydrolysis of selenium-rich Pleurotus ostreatus protein were as follows:The ratio of material to liquid was 1:30,the amount of alkaline protease was 4200 U/g,the hydrolysis temperature was 55 ℃,and the pH10.5,reaction time was 4 h.Under these conditions,the degree of hydrolysis of selenium-enriched Pleurotus ostreatus protein can reach 28.46%,the dissolution rate of protein was 82.85%,and the content of selenium in the hydrolyzed protein peptide was 2739.78 μg/g.In this study,the optimum conditions for the hydrolysis of selenium-enriched Pleurotus ostreatus protein by alkaline protease were determined,which has a certain reference value for the further study of selenium-enriched Pleurotus ostreatus.