Abstract: OBJECTIVE To determine the equilibrium solubility, oil/water partition coefficient and study the cyclodextrin inclusion complex of Enmein, provide the basis for the new preparation of Enmein. METHODS The equilibrium solubility of Enmein in different solvents were detected by HPLC. Flask shaking method was used to determine the oil/water partition coefficients of Enmein in different conditions. The Enmein inclusion complexes were prepared with HP-β-CD and HP-γ-CD. They were compared the change with solubility. RESULTS The equilibrium solubility of Enmein in water was (239.32±4.99)μg·mL^-1 at (25±0.5)℃ for 24 h, it was slightly soluble in organic solvents, and insoluble in medical oils. The octanol-water partition coefficient of Enmein was 4.64. Different pH and cyclodextrins had little effect on lgP. The solubility of inclusion complexes were increased, in which HP-γ-CD was the stronger. CONCLUSION Enmein has poor solubility in water and medical oils, and its absorption is less influenced by different pH and cyclodextrins. The bioavailability is significantly increased when Enmein is included by HP-γ-CD.