Abstract: To improve the extract rate of acid-soluble collagen(ASC) from cod skin,the acid concentration,extraction time and the liquid/material ratio were applied to accelerate the extraction process. With the extract rate of ASC as the response value,based on the single factor experiments,the factors influcing the extraction of ASC were optimized by response surface methodology according to the Box- Behnken central composite designs. The results showed that the acid contraction of 0.47 mol/L,liquid/material ratio of 1∶33(m∶v) and the extract time of 90. 2 h, the predicted extract rate and the actual extract rate were 37. 92 % and 37. 36 %respectively,the deviation was1.49%. The optimized of the factors influcing the extraction of ASC by response analysis methods was accurate and reliable,which gave a technical reference for the extraction of ASC from cod skin.