Lactic acid fermentation in Asia has been applied for various other purposes. It is used to prepare savory acidic dishes with vegetables and cereals, to ensure the quality of rice wines, and to make beverages from plant materials. However, the most important role of lactic acid fermentation in the Asian diet is the preservation of perishable vegetables and seafood in sanitary and safe conditions. The organic acids, mainly lactic acid and acetic acid, produced by lactic acid bacteria are effective antimicrobial agents, and they reduce the pH in the foods to prevent the growth of most hazardous food microorganisms. However, storage time of these products was shortly. Therefore, the study aims to find the optimal conditions to extend storage time of sour fermented shrimp with two main experiences (i) the effect of ratio of chitosan (0.2%, 0.3%, 0.4%, 0.5%) and treatment methods (soaked for 20 minutes or added into the product), (ii) the effects of types of additives (sodium benzoate and potassium sorbate), ratio of their additives (0.050, 0.075, 0.100, 0.125, 0.150%), and storage temperature (room temperature and 4^oC) on the quality and storage time of the product were studied. The results showed that the best sensory of sour fermented shrimp product until 3-week stored at 4^oC was obtained by soaking shrimp in 0.4% chitosan solution for 20 minutes. Total titratable acidity and pH were 2.0% and 3.6, respectively. The product still kept stable and ensured microbiological standard as well with total bacterial count (7.8*10⁵cfu/g). For additives, with added 0.1% sodium benzoate until 5 weeks stored at 4^oC provided the best sensory of products, total titratable acidity of 2.24%, pH 3.53, total bacterial count (8.4*10⁵ cfu/g).