In order to highly efficiently utilize the protein resource in Silybum marianum's kernel,the effects of protease types and parameters on the antioxidant activity,hydrolyzing degree,nitrogen recovery,and bitterness value in hydrolysate was researched.The results showed that papain was the optimal protease compared with trypsin,neutral,alkali,and complex protease for hydrolyzing Silybum marianum's kernel protein to obtain the higher antioxidant activity,proper degree of hydrolysis and nitrogen recovery,and lower bitterness.When the parameters for hydrolyzing were set at 45~50℃,240~270 min and pH 6~7,the antioxidant activity,the hydrolyzing degree and nitrogen recovery,and the bitterness value could maintain at 14 U/mg proteins,above 20% and 60%,and below 2,respectively.Under these conditions,the hydrolysate possessed wholly good quality and could be used as a component for functional food development.