NOVELTY - Forming atazanavir intermediate((2S,3R)-4-chloro-3-hydroxy-1-phenyl-butyl-2-yl)carbamate, involves subjecting (S)-t-butyl (4-chloro-3-carbonyl-1-phenyl-2-yl) carbamate substrate to asymmetric reduction under ketoreductase enzyme effect, and fermenting glucose by glucose dehydrogenase coenzyme, where method includes adding substrate in reactor having auxiliary solvent, mixing, weighing glucose ketone reductase enzyme powder, adding glucose dehydrogenase and cofactor in buffer solution, and adding to reactor, determining conversion rate, where co-factor is NAD/NADH or NADP/NADPH.    USE - For preparing atazanavir's intermediate i.e.((2S,3R)-4-chloro-3-hydroxy-1-phenyl-butyl-2-yl)carbamate (claimed), where atazanavir is protease inhibitor type antiviral medicine used for treating AIDS.    ADVANTAGE - The method exhibits high reaction efficiency and provides improved biological conversion process, and has important application values. The method is simple and causes no environmental pollution, has mild conditions, forms little wastes, and has good industrial application values.    DETAILED DESCRIPTION - Biological preparation of atazanavir intermediate, where atazanavir intermediate is ((2S,3R)-4-chloro-3-hydroxy-1-phenyl-butyl-2-yl)carbamate, involves taking (S)-t-butyl (4-chloro-3-carbonyl-1-phenyl-2-yl) carbamate as substrate, subjecting the substrate to asymmetric reduction reaction under the ketoreductase enzyme effect to form atazanavir, conducting common fermentation of glucose by taking glucose dehydrogenase coenzyme, where the method is carried out as follows: adding the substrate in a reactor containing auxiliary solvent and stirring uniformly, weighing glucose ketone reductase enzyme powder, adding glucose dehydrogenase and cofactor in water phase buffer solution having pH of 8-9 and adding the obtained mixed solution to the reactor, stirring, controlling the temperature at 32 degrees C to 34 degrees C, starting reaction, and determining HPLC detection reaction conversion rate, where conversion rate is greater than or equal to 96%, ending the reaction, where the mass-volume rate of substrate is 0.05-0.2 g/ml, and enzyme, cofactor, glucose, and substrate's feeding mass ratio is0.02 to 0.03:0.001 to 0.005:0.8 to 1.2:1, the co-factor is NAD/NADH or NADP/NADPH, where the auxiliary solvent is acetonitrile and/or toluene.