Abstract: OBJECTIVE To select out a complexing extracting agent suitable for extracting and separating the liquiritin, and study the effect of composition changes of complex extractant on the extraction of liquiritin from Glycyrrhizae Radix Et Rhizoma ultrafiltrate. METHODS The single extraction rate of liquiritin and glycyrrhizic acid were taken by the complex extractant as an index, through single factor experiments, on the basis of investigating the extraction of index components in licorice ultrafiltrate by a variety of binary complexing extractants. U₅(5³) was adopted to uniformly design and optimize ternary complexing extractants containing two complexing agents, to further improve the extraction efficiency of liquiritin complexing and reduce costs. RESULTS Tributyl phosphate (TBP) in ternary complex extractant had no synergistic extraction effect on trialkyl phosphine oxide (TRPO) complex extraction of liquiritin. Preferably, the single extraction rate of liquiritin by the complex extractant composed of 15% TRPO + 85% sulfonated kerosene was 99.6%, and the single extraction rate of glycyrrhizic acid by the complex extractant was 8.3%. CONCLUSION The optimized complexing extractant has strong extraction capacity and high selectivity for liquiritin in Glycyrrhiza ultrafiltrate, and can be used for complexing extraction of liquiritin in Glycyrrhiza ultrafiltrate.