Melanosis is major problem of crustaceans duringtheir rigor mortis storage. This study for the firsttime was designed to optimize the formula of preservativesto maintain the color feature of Pacific white shrimp usingresponse surface methodology. A three-factors-three-levelsBox-Behnken design was applied to evaluate the effect ofchitosan, citric acid and L-cysteine on color features (L*,a*, b* and DE) of Pacific white shrimp. It was found thatthe increasing rate of DE was retarded by the higher concentrationsof chitosan, citric acid and L-cysteine in acertain range. The optimal formula for inhibiting theincrease of DE was 1.36% chitosan, 0.47% citric acid and0.31% L-cysteine. Under the optimal pretreated conditions,the predicted DE of shrimp after 8 days of storage was14.59, close to the measured values (14.49). These resultsindicated that the optimal combined preservatives couldretard the decrease of lightness and the aggregation of DEand melanosis effectively, and might be a potentialapplication for retarding melanosis and extending shelf lifeof Pacific white shrimp.