In the study, an extract technology of cow leather collagen polypeptide with complex enzyme preparation was discussed, using the cow leather collagen as experimental raw material, which was made in our lab. The adding procedure and proportion of the two kinds of enzyme including the papain and trypsin, were determined, the hydrolysis degree of collagen as indicator. Meanwhile, the optimizing interval of technical factors was obtained by single factor method. The experimental results showed that the optimal conditions of collagen polypeptide extraction from collagen protein were as follows, the proportion of enzyme activity of the papain and trypsin was 3:1, addition of 650 u/ml enzyme preparation, hydrolysis temperature of 50℃, pH 7.0 for 7h. The hydrolysis degree can reach 32.02% under the optimization conditions.