Objective\ To set up a fast digesting and measuring method for protein in food.\ Methods\ The old digesting way of kjeldhl method (for nitrogen determination) was improved. Hydrgen peroxide (8.8mmol/L) and sulphuric acid mixed solution (4∶1, V∶V ) was used as digesting reagent. Samples were measured with methylaldehyde method.\ Results\ The digesting time was reduced from two hours to ten minutes. The results of our measuring method were basicly the same as that of kjeldhl method (for nitrogon determinati...