Objective: To optimize the extraction condition of polysaccharide from Schisandra chinensis. Aqueous two-phase extraction（ ATPE） method was used, based on Box-Behnken design with Response surface methodology（ BBD-RSM）.
Methods: solvent volume,K2HPO4 and PEG6000 were selected as the investigation factors by the single-factor experiment, and the overall desirability（ OD）of phase volume ratio, partition coefficient and extraction rates were the reponse value. BBD-RSM was used to optimize the extraction process. .
Results: The optimal parameters were as follows,the solvent volume was 5 m L,the addition amount of K2HPO4 was 1. 0 g, the addition amount of PEG6000 was 1. 8 g and centrifugation time was 9 min, which indicated that the model had a good predictability. The predicted value was 0. 950,and the deviation between observed and predicted values was 3. 94%
Conclusion: The ATPE technology is easy to operate and cost-effective for the extraction of polysaccharides from Schisandra chinensis.