Abstract: The effects of pre-heating temperature and time on enzymolysis characteristics of sweet potato protein by Alcalase was investigated. The single-factor experiments and response surface methodology (RSM) were applied to determine the pre-heating treatment parameters for the enzymatic hydrolysis by Alcalase. The regression models of the degree of hydrolysis (DH) and trichloroacetic acid-nitrogen solubility index (TCA-NSI) were established between impact factors and indexes. The validity of the models and interactions of impact factors were analyzed. The results showed that the effects of pre-heating treatment on DH and TCA-NSI of sweet potato protein was significant (P<0.05), and the optimum pre-heating treatment conditions were obtained as follows: temperature 92℃, time 13 min. Under the optimized conditions, DH and TCA-NSI were 26.32% and 84.33%, respectively. Compared with the direct hydrolysis of native sweet potato protein, DH and TCA-NSI under the optimum pre-heating treatment parameters showed increases of 15.89% and 53.37%, respectively.