The purpose of this study was to determine the optimal condition of enzymatic production of cereal milk. The commercialenzyme pectinase (Pectinex Ultra SP-L) assisted in the extraction process and an experimental design using responsesurface methodology (RSM) was utilized to further optimize the yield. The condition parameters were incubation temperature(X1; 25, 35, and 45°C) hydrolyzing time (X2; 60, 120, and 180 min) and concentration of enzyme (X3; 1, 2, and 3% v/w). Thereducing sugar content can be predicted using equation: reducing sugar = 12.292 +1.776(x1) +2.296(x2) +0.612(x2x3) +1.159(x12)–2.533(x32) with R2 = 0.781, p0.05). The relationship between incubation temperature, hydrolyzing time, and enzyme concentrationon reducing sugar content was shown in terms of linear, quadratic, and interaction. The optimal condition was incubationtemperature of 35°C, hydrolyzing time 120 min, and 2% (v/w) pectinase. Under the optimum condition, the reducingsugar, protein, fat, and antioxidant activity of cereal milk increased 3.44, 1.59, 1.14, and 1.03–fold, respectively, compared with control. This research concluded that enzymatic hydrolyzed cereal milk is a potential source of protein, fat, and antioxidantsactivity.