Objective To improve the quality of Guhan Yangshengjing oral liquid,reduce the production cost and reduce pollution by ultrafiltration - nanofiltration combined technology. Methods With the retention rate of icariin as indicator,interception molecular weight,pressure,and temperature as factors. The optimum membrane concentration process was optimized by orthogonal experiment. Results The optimum ultrafiltration process were as follows: interception molecular weight was: 200Da,pressure was: 0. 8MPa ,temperature was: 25℃. Conclusion Ultrafiltrat...