Biscuits are popular with many people, including young and old man. In present, much attention is paid to biscuits taste and flavor, but proportion of protein from different material in biscuits is usually ignored. It results in less nutrition value. This can be improved by increasing protein biological value through proper mixture of different protein resources. The best optimization proportion of different material protein is quantitatively determined through mathematics model and the application of computer technology. This model is applied in the formula design of biscuit made of wheat flour protein, soybean protein and milk protein, the result is as follows: wheat flour protein: soybean protein: milk protein＝11:5:7.