In this paper,we use gluconolactone( GDL) and antibiotic to build an acidified system of simulated fermentation. Pediococcus pentosaceus protease was extracted and added into the acidified system and silver carp actomyosin,and then the changes of non-protein nitrogen( NPN),TCA-soluble peptides,turbidity and particle size were measured to research the extent of silver carp protein degradation,meanwhile changes in gel strength were measured.The results showed that protease caused the increasing of NPN and TCA-soluble peptides and the decreasing of turbidity and particle size,especially in pH 4. 5. In a word,these data comprehensive described that Pediococcus pentosaceus protease hydrolyzed protein and caused gel cracking of fermented surimi.