Abstract: The process of enzyme debranching corn starch was investigated. Based on the single factor experiment, the effect of pH, temperature and enzyme concentration on the yield of reducing value were optimized with Response Surface Methodology (RSM) . A mathematical model was established between the studied factors and the responses. The optimal conditions were as follows:temperature 56℃, pH5.1, and enzyme concentration 28.92U/g. The R2 of 0.9438 means that the results were in good agreement with predicted values and the model was useful for optimizing the enzyme debranching process.