Polysulfone membrane was used to treat the solution of tara tannin.The influencs of several factors such as the mole-cular weight cutoff,trans-membrane pressure,flow velocity,and temperature on membrane property and product quality were studied.The experimental results showed that,under the conditions of molecular weight cutoff of 10000,trans-membrane pressure of 0.2MPa,flow velocity of 2.0m/s,and temperature of 40-45℃,the tara tannin with turbidity≤0.5NTU,and purity ≥85% was obtained.