The hydrolysis by Alcalase can alter the structure and emulating property of corn protein.The factors effecting on Alcalase hydrolysis of corn protein were investigated by response surface methodology.The best hydrolysis results can be obtained by conducting the hydrolysis at 50℃ with water addition 4g/g protein, 3035-Ansen units/g protein,pH 9,and 120 min;under such condition,the maximum emulsified activity of enzyme 22.19 m2/g in theory and 23.75 in the experiment were obtained,with an increase of 42% compared to the original corn protein.