NOVELTY - Method for preparing medicine intermediate deacetyl-7-aminocephalosporanic acid (D-7-ACA), involves diluting cephalosporin C sodium salt concentrated solution, adding the solution to immobilized cephalosporin C (CPC) acylase and immobilized acetyl esterase, performing enzymatic reaction, finishing reaction, obtaining final lysate, adding the final lysate to crystallization tank, cooling the lysate, adding hydrochloric acid solution to adjust the pH, controlling crystallization temperature, filtering the product, washing the product, and vacuum drying the product.    USE - The method is useful for preparing medicine intermediate D-7-ACA (claimed).    ADVANTAGE - The method is simple, rapid, environmentally-friendly, cost-effective and sustainable, increases utilization rate of cephalosporin C fermentation components, avoids three-step enzymatic process using liquid oxygen, has mild reaction conditions, utilizes simple equipments, provides high yield and less by-products, and conducive for the development of green pharmaceutical industry.    DETAILED DESCRIPTION - Method for preparing medicine intermediate deacetyl-7-aminocephalosporanic acid (D-7-ACA) by two-enzyme-one step method and using cephalosporin C sodium salt concentrated solution as substrate, involves (a) diluting cephalosporin C sodium salt concentrated solution to 28000-32000 u/ml, using 5 %mass aqueous ammonia to adjust the pH of the solution to 6.5-7.5, adding the solution to immobilized cephalosporin C (CPC) acylase and immobilized acetyl esterase, performing enzymatic reaction at 18-25 degrees C, adjusting the pH to 8-8.5 using 3-8 %mass aqueous ammonia, finishing reaction and obtaining final lysate, where the ratio of cephalosporin C sodium salt diluted liquid immobilized CPC acylase is 4000-5000 and the ratio of cephalosporin C sodium salt diluted liquid and immobilized acetyl esterase is 4000-5000, and (b) adding the obtained final lysate to crystallization tank, cooling the lysate to 0-10 degrees C, dropwise adding 10-20 %mass hydrochloric acid solution to adjust the pH to 3-5, controlling the crystallization temperature, filtering the product, washing the product using methanol, and vacuum drying the product.