To improve protein extraction efficiency from broken indica rice, the technology of extraction of broken indica rice protein extracted by neutral proteinase enzymatic extraction was optimized by central composite design and response surface analysis based on the results of Min-Run Res IV factorial design and steep accent experiment. The second-order polynomial nonlinear regression equation and mathematical model were established. The accuracy of the model was validated. The effects of enzyme loading amount X1, enzymolysis time X2, solid-liquid ratio X3 on rice protein extraction rate were analyzed with protein extraction rate and protein purity as the appraisal indexes. The optimum conditions were, enzyme loading amount 0.98%, solid-liquid ratio 1∶10.20, enzymolysis time 74.4min, pH 7.0 and 50℃. The confirmation experiments were carried out under the optimum conditions, the PER was 89.82%±1.06%（n=3), which was well agreement with the predicted value (91.23%). The deviation between the measured and predicted condition was -1.55%. The rice protein purity was 81.02%.