Abstract: Ultra-filtration was used to isolate and purify bromelain , and operating pressure, temperature, concentration and other factors were investigated on the impact of two important indicators for the flux of membrane and rejection ratio of ultra-filtration. The results indicated that the purification ratio of bromelain reached 89.4 times, and recovery ratio of enzyme activity was related up to 79.3%, which was more 81.4 times than the TiO2 porous ceramic column. Furthermore, the recovery ratio was increased by 31.3% in the desired state (pressure (0.184±0.007) MPa, temperature (10±0.5) ℃, concentration ratio 16) . Test venues and apparatus used amount were significantly reduced when isolation and purification of bromelain was used of the ultra-filtration method. Meanwhile, the method was played a role in a highly purified effect because good recovery ratio of enzyme activity and high ralative activity were obtained. In addition, the procedure was convenient in operation, small in volume, large in capacity, reflecting that the ultrafiltration method was relatively suitable for the production of high purity bromelain.