Abstract: α-amylase from soybean seeds was purified to apparent homogeneity by affinity precipitation via entrapment in alginate with 84% recovery and about 20-fold purification. The α-amylase activity and stability was characterized at various pH and temperature. Response Surface Methodology (RSM) using two-level-two-factor full factorial Central Composite Design (CCD) model was employed to optimize process parameters like pH and temperature which affects the kinetics of α-amylase catalyzed hydrolysis of starch. The results predicted by the design were found in good agreement (R2 = 97.85%) with the experimental results indicating the applicability of proposed model. The multiple regression Analysis and ANOVA showed the individual and cumulative effect of pH and temperature on enzyme activity indicating that the activity increased with the increase of pH unto 5.5 and temperature 75°C. Thus, the RSM was successful in determining the optimum reaction conditions for starch hydrolysis by α-amylase.