Abstract: This article mainly aimed at the aqueous phase obtained from the extraction of the camellia seed oil with ethanol solution and studied the separation of tea saponin by ultrafiltration method.Material of ultrafiltration membrane, the aperture of the membrane, the initial concentration of tea saponin, the p H of the aqueous phase and the amount of water added in later period of ultrafiltration were studied to explore their effects on the yield and purity of the tea saponin. The results showed that when 10 k membrane of PLCGC material was used and diluting the aqueous phase to 4 times ( 13.13 mg/m L tea saponin) , adjusting the aqueous phase p H as 7.0 and adding 3 times water during later ultrafiltration period, the transmittance ratio and purity could reach 64.39% and 84.16%.Characterize the final purified tea saponin by IR and LC-MS.The result showed the tea saponin was in a high purity and it basically conformed to the features of standard substance. Therefore, ultrafiltration was an effective method to separate the tea saponin from the aqueous phase.