Objective: This study aimed to explore the changes of polypeptides and free amino acids in Acetes chinensis before and after autolysis. Methods: The optimal pH and temperature of the endogenous protease of the A. chinensis were determined and the autolysis conditions were optimized. Then changes of a polypeptide, amino acid and molecular weight in the product before and after autolysis were studied under the optimal conditions. Results: The optimum temperature and pH of endogenous protease were 45 ℃ and 8.0 respectively. Under the optimal autolysis conditions of pH 8.0, temperature 40 ℃, and reaction time 4 h, the polypeptide concentration of A. chinensis surimi was 10.36 mg/mL. The content of total free amino acids, essential amino acids and hydrophobic amino acids increased, the proportion of bitter amino acids increased by （4.54±0.02）%, while the proportion of umami amino acids and sweet amino acids decreased by （3.46±0.02）% and （1.78±0.01）% respectively. The proportion of degradation products with molecular weight less than 1 000 Da increased from 70% to 87%. Conclusion: Autolysis technology can degrade the protein of A. chinensis and release small molecule peptides and amino acids.