In this study, an immobilized metal ion affinity membrane (IMAM) was prepared and used to immobilize penicillin G acylase (PGA). The stability of storage of the immobilized PGA membrane (IPM) was tested. When stored in deionized water (DI) at 4°C, only 19% residual activity of IPM was retained for 10 days. However, when stored in 10mM phosphate buffer (PB, pH 8) with 0.1% NaN3, the IPM can retain 99% of its activity for a 10-day reaction and storage test. The feasibility of the IPM regeneration after a long period of reaction was investigated. When using 100mM EDTA as the stripping solution, the re-immobilized capacity for PGA is only 52% of the original one after 4 regenerations. When the regeneration process was modified by using the stripping solution (300mM NaCl, 25mM EDTA, 20mM PB, pH 8) for 30min, then immersed in 0.5M HCl and 0.5M NaOH respectively for 10min, the resulting IMAM can reserve 99% PGA immobilized activity after 5 regenerations.