Objective To optimize the process parameters for the purification of the extract solution of Radix Astragali and Radix Puerariae in Huangqi Gegen Decoction prescription by ceramic membrane ultrafiltration. Methods With the extract solution of Radix Astragali and Radix Puerariae (in the proportion of 1 : 2) as the study object, and with solid content, puerarin transfer rate and characteristic peak area as indicators, the membrane pore size, ultrafiltrate temperature and ultrafiltration pressure were selected as the main factors, and single factor test and L9 (34) orthogonal test were used to optimize purification conditions. Results With comprehensive scores as the evaluation index, the optimized conditions for the extract solution were as follows:membrane pore size was 100 nm, ultrafiltration temperature was 35 ℃, and ultrafiltration pressure was 0.18 MPa. The main influence factors of ceramic membrane pore size and ultrafiltration pressure had obvious effects on the refined process(P<0.05).Conclusion The method of purification of the extract solution of Huangqi Gegen Decoction prescription by ceramic membrane ultrafiltration is feasible , and the results will provide reliable experimental evidence for the purification of Chinese herbal medicine extract with ceramic membrane.