Abstract:In this paper， the applicability of ultrafiltration membrane（UF） in the purification process of L-ara－ binose fermentation liquid was studied. The influence rules of pore size， operating pressure， operating tempera－ ture， and cross-flow velocity on the flux of ultrafiltration and downstream procedures （ion exchange） were in－ vestigated. The results showed that： the optimum pore size was 1.0 μm；the optimum operating pressure was 0.4 MPa；the optimum operating temperature was 50 ℃； the optimum cross-flow velocity was 6 m/s； the average flux was 119.8 L/（m2·h）. The optimum cleaning condition was hot water（65 ℃） and chemical cleaners， and the recovery was more than 95 % after cleaning. Compared with the classical pad filtration process， UF technology can promote the downstream ion exchange capacity more than 51.45 %； which was 68.02 %， Compared to the classical rotary drum vacuum filtration process. In conclusion，UF technology can intercept yeast， bacteria， gelatin， protein and pigments and other impurities in Yeast， bacteria， gelatin， protein and pigments and other impurities efficiently； keep downstream ion exchange production running smoothly； increase the quality of L-arabinose product.