Abstract: OBJECTIVE To prepare insoluble porosity membrane capsules containing verapamil hydrochloride and investigate their in vitro drug release. METHODS With cellulose acetate(CA) used as capsule materials and PEG400 as plasticizer, the insoluble porosity membrane capsules were prepared by dip plastic method. Effects of different types and ratio of receiving medium and different porosity membrane capsules on drug release behavior were investigated. With scanning electron microscope, surface and cross-section of capsule shell were also observed. RESULTS Drug release rate enhanced with increasing pore-formers Poloxamer (F68). Profile of drug release showed a stable trend when citric acid was added in capsule formulation. CONCLUSION Insoluble porosity membrane capsules of verapamil hydrochloride give a sustain drug release behaviour in vitro. With monitoring the inner circumstance in capsules, a stable drug release rate can be obtained in vitro.