In this study the potential use of ionic liquid-based aqueous two phase system (ILATPS) for the extraction of ursolic acid from Cynomorium songaricum Rupr was evaluated and optimized. The effects of independent variables(the mass fraction of [Bmim]Cl and KH2PO4, mass fraction of crude extract, mass fraction of NaCl and pH)were evaluated by single factor analysis. The optimization ATPS of 25%[Bmim]Cl-21%KH2PO4were selected based on their higher upper phase partitioning coefficient and the recovery .Using the optimized ILATPS solvent, the Box-Benhnken Design results showed mass crude extract 8.5%,NaCl 1%, pH4.7 were the optimal ILATPS extraction conditions. Maximum yield of extracted ursolic acid from the experiments was determined to be 97.85% under the optimal conditions, which was in good agreement with the predicted one of 98.3%. In conclusion, the optimized process has good reliability.