The dissolution of midecamycin capsules was investigated. The dissolution of midecamycin capsules, prepared by different formulations, granulating technologies and packages, were evaluated during stability experiment The initial dissolution of midecamycin capsules, prepared by different formulations, granulating technologies and packages, were approx. 100% of the dosage within 20 min, but the dissolution rate decreased to below 50% within 60 min in every formulation with midecamycin produced in China after storage, and at the same time the dissolution rate was above 90% within 20 min in every formulation with midecamycin produced in Japan after storage. The dissolution rate of the capsules, which prepared with midecamycin produced in China, decrease rapidly after storage. But the capsules prepared with midecamycin produced in Japan are stable after storage.