Abstract: In order to keep Penaeus Vanmamei fresh, restrain melanosis and extend its shelf-life, response surface method (RSM) was used in the experiments to get a complex preservative combined with phytic acid, chitosan and ε-polylysine. Results showed that the best combination of the complex preservative was that of phytic acid 0.07%, chitosan 1.5% and ε-polylysine 0.1%. By treatment with the combined preservative, the sensory evaluation, pH value, total volatile basic nitrogen (TVB-N), total bacteria count (TBC) and trimethylamine(TMA) of Penaeus vannamei were determined under the storage of (4±1)℃ to evaluate the quality of samples. It was found that the combined preservative could keep a better sensory quality, and the shelf-life under the storage of (4±1)℃ was prolonged from 3-4 to 7-8 days. The total bacterial count (TBC) was only 5.7 lg(CFU/g) on the 10th day. The conclusions can provide a technical support for the optimization of natural preservative and extension of preservation of Penaeus Vanmamei.