Abstract: OBJECTIVE The OFLO/MMT nanocomposite was prepared to find the new drug delivery material and develop the new dosage of ofloxacin. METHODS The OFLO/MMT nanocomposite was prepared by the solution ion exchange and the factors such as drug initial concentration, reaction time and the reaction temperature on the drug loading of the nanocomposite were studied by the single factor method and the intercalation reaction condition was optimized. The structure of the nanocomposite was characterized by Ultraviolet spectrum, FTIR and DTA. Moreover the in vitro release behaviors of the OFLO/MMT in different pH medium were investigated. RESULTS The optimal conditions of the intercalation reaction were as follows:the initial concentration was 2.60 mg·mL^-1, the temperature was 25℃ and the time was 2 h. The sustained release behavior was obviously observed in vitro release experiment for the OFLO/MMT composite, and the release kinetic behavior in acid medium was different from that of basic medium. Generally, it was more easily for the OFLO/MMT release in acid solution (pH 1.2). CONCLUSION The ofloxacin intercalated into the layer of the montmorrilloniite releases slowly from the composite, the montmorrillonite has a great potential as a delivery host in the pharmaceutical field.