[Objective]To determine equilibrium solubility under different pH value and the oil-water partition coefficient of dauricine in Octanol buffer system.[Methods] To determine the concentration of dauricine by HPLC and the equilibrium solubility by saturation method;to determine dauricine’s concentration in octanol and water phase so that its oil-water partition coefficient can be calculated.[Results]The concentration of dauricine increased with the addition of pH value at 37℃;the oil-water partition also increased with the addition of pH value; the logP value of dauricine was around 0.5 when pH value remained in the range of 6.8-8.0(equavelent to the pH condition inside small intestine),which indicated it has higher lipid solubility.[Conclusion] The equilibrium solubility and oil-water partition coefficient of dauricine were both under the influence of pH value;the methods established in this experiment was able to accurately determine the equilibrium solubility and oi-water partition coefficient of dauricine and to procast its interrior process. [Methods] To determine the concentration of dauricine by HPLC and the equilibrium solubility by saturation method; to determine dauricine’s concentration in octanol and water phase so that its oil-water partition coefficient can be calculated. [Results] The concentration of dauricine increased with the addition of pH value at 37 ° C; the oil-water partition also increased with the addition of pH value; the logP value of dauricine was around 0.5 when pH value was in the range of 6.8-8.0 (equavelent to the pH condition inside small intestine), which indicates it has higher lipid solubility. [Conclusion] The equilibrium solubility and oil-water partition coefficient of dauricine were both under the influence of pH value; the methods established in this experiment could able to determine the equilibrium solubility and oi-water partition coefficient of dauricine and to procast its interrior process.