Abstract In this paper, an aqueous two-phase system (ATPS) based on ethanol/NaH2PO4 was used in separation and purification of chlorogenic acid (CGA) from ramie leaf. CGA was firstly extracted from dried ramie leaf powder by ethanol solution, then was added into ATPS for further purification. During the ATPS extraction procedure, the influencing parameters of type and concentration of salt, extraction temperature and pH were investigated. The experiments results demonstrated the CGA were extracted into alcohol-rich phase with impurities being extracted into salt-rich phase, the phase-forming components were recycled to reduce the cost after extraction. Furthermore, the thermodynamics and kinetics during the extraction procedure were simultaneously studied for the first time. This much easier, greener and cheaper alcohol/salt ATPS was more feasible for large-scale production.