The invention relates to a method for preparing cefprozil in a pH responsive regenerative double aqueous phase system. The method comprises (1) preparing two double-aqueous phase systems, (2) orderly adding 7-APRA, D-p-hydroxyphenylglycine methyl ester hydrochloride into the systems, adjusting solution pH to 5.00-6.50 and controlling a solution temperature in a range of 10-30 DEG C, (3) adding immobilized penicillin acylase into the solution obtained by the step (2), and (4) standing the mixed solution, removing the immobilized penicillin acylase, adjusting the pH of the reaction solution, recovering P<ADBA>/<PMDB> and P<ADB>/P<MDB> polymers of the double-aqueous phase systems, feeding the supernatant to a crystallization section, carrying out crystallization, and carrying out centrifugation, washing and drying to obtain a product. The method reduces a chemical synthesis cost, improves a low product conversion rate of the monohydrolase catalytic reaction, effectively improves a yield, simplifies the operation, reduces a cost and realizes easy recovery of the double-aqueous phase systems.