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Traditional methods,such as diastereomeric crystallization [1],asymmetric synthesis and kinetic resolution[2],o/w biphasic extraction [3],preparative chromatography [4],capillary electrophoresis [5] etc.were used for chiral separation and purification of enantiomers.An alcohol/salt-based aqueous two-phase system (ATPS) were employed for enantioseparation of (R,S)-mandelic acid (MA) and (R,S)-α-cyclohexyl-mandelic acid (α-CHMA) in this paper.Six kinds of ATPSs were studied to select an optimal chiral separation system.Sulfonated beta-cyclodextrin (S-β-CD) with different degree of substitution (DS) was considered as chiral selector.To optimize the optimal chiral separation and cognition conditions,the influencing parameters such as concentration and type of S-β-CD,concentration of C2H5OH and (NH4)2SO4,temperature and pH were studied in detail.The experimental results showed that the C2H5OH/(NH4)2SO4 ATPS had the optimal chiral recognition ability for MA.The partitioning behaviors of enantiomers were mainly dependent on the type of chiral selector.Concentration of C2H5OH and (NH4)2SO4 also had significant influence.This system was more beneficial for recognition of MA,under the optimal conditions,the maximal separation factor (α) was 1.65 and enantiomeric excess in upper phase (e.e.upper) was 15.7% by employing S-β-CD(2) as chiral selector in the C2H5OH/(NH4)2SO4 ATPS.The alcohol/salt ATPS is a more economical and efficient system,furthermore,it has advantages such as easy recovery of ethanol by evaporation and potential large-scale production.