Abstract: A method of extraction for the anthraquinones from Rheum palmatum L.was developed by ultrasonic-assisted small molecular water-miscible alcohol aqueous two-phase extraction.The content of total anthraquinones was determined by high-performance liquid chromatography,and the best aqueous two-phase system,1-propanol/Na₂SO₄,was screened with yield of anthraquinones as an index.In order to integrate extraction and hydrolysis for anthraquinones from Rheum palmatum L.,the acid was added to the systems.The factors influencing the extraction yield were investigated in detail and the experimental conditions were optimized using response surface methodology (RSM).The final optimized conditions were,temperature 75 ℃,extraction time 30 min and liquid/solid ratio 20 mL/g.Under the optimized conditions,the highest yield of five anthraquinones was up to 19.59 mg/g.The experimental results showed that the method had the advantages of fast，efficient,low-cost,and so on.It provided some new ideas for industrialized production of extracting on the efficacious components from plants.

Key words: ultrasonic-assisted extraction, aqueous two-phase systems, anthraquinones of Rheum palmatum L., high-performance liquid chromatography