Objective To establish the method of measuring dissociation constants and oil-water partition coefficients of mangiferin. Methods Comparing two measurements for dissociation constants of mangiferin， which are ultraviolet spectrophotometry and pH – HPLC. Measuring oil-water partition coefficients of mangiferin between n-octanol and different pH buffer solution by HPLC and shaking flask method. Results Studying on the HPLC and ultraviolet spectrophotometry method for the dissociation constants of mangiferin. They got almost the same results which respectively are 6.5 and 6.1. Studying on the HPLC and shaking flask method for measuring the oil-water partition coefficients of mangiferin. The oil-water partition coefficients of mangiferin were almost the same， while the pH of buffer solution was between 2.0 to 5.0. But they should recede considerably， while the pH was between 6.70 to 8.18. That means the lipid solubility of mangiferin increased and the water solubility of it decreased in acidic conditions. While that was diametrically opposite in alkaline conditions. Conclusion The Methods， which were established for measuring dissociation constants and oil-water partition coefficients of mangiferin， HPLC method were accurate， repeatable， convenient and rapid.