Abstract: The study investigated Chinese sturgeon recombinant cystatin gene expression in yeast Pichia pastoris, the inhibitory effect of product on papain, and the trend of myosin′s content change in processing of silver carp when cystatin were added or not. The result shows that recombinant cystatin can inhibit papain effectively, and the inhibitor curve is: y = 0.0234x + 0.0059. The result of SDS-PAGE of surimi samples were analyzed by the AlphaeaseFC^TM software and it turned that the status that myosin was hydrolyzed by endogenous proteinases were relieved for 45 minutes heating time when 0.0215 mg · g^-1 cystatin was added to surimi.