Abstract: In order to explore the optimum extracting conditions with non-denatured principle for leaf protein from mulberry, use Na₂HPO₄-citric acid buffer to extract mulberry leaf protein and study the rate of protein degradation. Through 4 factors and 3 levels orthogonal experiments, 4 factors including material-liquid ratio, extracting time, extracting temperature and pH value were optimized. Protein yield and protein extraction rate were 2 indicators to find the most optimum processing parameters. The results showed that the most optimum conditions were as follows: pH 7.6, material-liquid ratio 1:10, extracting time 25 min, extracting temperature 15℃. As soon as the author beated fresh leaves the cell walls must be destroyed, the protein in the cell might decompose by the action of the autolysis enzyme, which would lead to a lower leaf protein extraction rate. Under the optimum conditions the author added a certain amount of EDTA-2Na as a protease inhibitor before beating so as to enhance the rate of protein extraction. It was found this optimum concentration by observing the protein degradation curve with different concentrations of EDTA- 2Na. Ultimate it showed that during extraction, 5 mmol/L of EDTA-2Na could minimizes protein degradation.