The condition of the preparation of bovine casein phosphopeptides by alkly hydrolysis casein and optimized by response surface methodology were studied.On the basis of single factor experiment and Centure-Composite Design principles,three factors at three levels response surface methodology was applied to build the model.The degree of hydrolysis was used as response value.By analyzing the response surface,the optimal processing was obtained as follows:hydrolysis time 90 min,temperature 60.04℃,pH 7.73,and enzyme-substrate ratio 2.3%,the actual hydrolysis degree was 20.40%.Under the above hydrolysis conditions,casein phosphopeptides content was 6.8%and its physicochemical characters was also tested.