Abstract: OBJECTIVE To investigate the solubilization effects of the inclusion complex of pinocembrin with hydroxypropyl-β-cyclodextrin (HP-β-CD) in aqueous solutions at various pH and to determine the constitutive molar ratio of pinocembrin-hydroxypropyl-β-cyclodextrin inclusion complex and its stability constant．METHODS The solubilization experiment was performed by the phase-solubility method at 25 ℃．The concentration of pinocembrin was determined by the UV spectrophotometric method．RESULTS The apparent solubility of pinocembrin was enhanced noticeably with the increase of HP-β-CD concentration and the increasing pH values．The apparent stability constants were calculated respectively．The molar ratio of the inclusion complex at various pH were studied．The application of HP-β-CD to parenteral formulations of pinocembrin was discussed preliminarily．CONCLUSION An inclusion complex of pinocembrin and HP-β-CD can be formed．