The invention discloses a processing method for continuously purifying tea saponin. The method comprises the following steps: 1, finely filtering a tea saponin solution obtained after extraction; 2, allowing the finely filtered tea saponin solution to enter a membrane with the permeable molecular weight of 10000 to carry out fine filtration and crude separation, and allowing the permeate solution to enter a membrane with the permeable molecular weight of 5000 to carry out primary purification; 3, allowing the obtained primarily purified permeate solution to enter a membrane with the permeable molecular weight of 3000 to carry out secondary purification; 4, allowing a membrane separation permeate solution obtained in step 3 to enter a membrane with the permeable molecular weight of 400 to carry out nanofiltratio; and 5, drying or concentrating a nanofiltration trapped fluid to obtain purified tea saponin, and reusing the obtained permeate solution as a solvent in an extraction system. The method effectively improves the purity of the tea saponins, and also realizes increase of the production efficiency and effective reduction of the production cost and one-time investment because the purification process is simple and is easy to know.