[Objective] To optimize the extraction technology of anthraquinone derivatives from RADIX ET RHIZOMA RHEI by continuously biphasic hydrolysis extraction. [Method] Anthraquinone derivatives were extracted from RADIX ET RHIZOMA RHEI by continuously biphasic hydrolysis extraction. Content of anthraquinone derivatives was detected by UV Spectrophotometry. With the total content of anthraquinone derivatives as the index, L9(34) orthogonal test was conducted in order to select he optimal extraction technology. [Result] The optimal extraction technology was as follows: 1∶10 solid-liquid ratio (W/V, g/ml), 25 mol/ml sulfuric acid solution, and 5 h extraction time of biphasic hydrolysis. [Conclusion] This method was simple and repeatable. [Objective] To optimize the extraction technology of anthraquinone derivatives from RADIX ET RHIZOMA RHEI by continuously biphasic hydrolysis extraction. [Method] Anthraquinone derivatives were extracted from RADIX ET RHIZOMA RHEI by continuously biphasic hydrolysis extraction. Content of anthraquinone derivatives was detected by UV Spectrophotometry. With the total content of anthraquinone derivatives as the index, L9 (34) orthogonal test was conducted in conducted to order to select he optimal extraction technology. [Result] The optimal extraction technology was as follows: 1:10 solid-liquid ratio (W / V , g / ml), 25 mol / ml sulfuric acid solution, and 5 h extraction time of biphasic hydrolysis. [Conclusion] This method was simple and repeatable.