A method of ultrasonic. assisted ionic liquid. salt aqueous two. phase extraction coupled with high. performance liquid chromatography(HPLC) was developed for the determination of the contents of five rare ginsenosides[20(S)-Rg(2), 20(S)-Rh-1, Rk(3), 20(S)-Rg(3) and Rk(1)] in Panax notoginseng(Burk.) F. H. Chen(Sanqi). The factors influencing the ultrasonic. assisted extraction were investigated in detail. Under the optimized conditions, satisfactory extraction efficiency was achieved with the recoveries ranging from 92. 07% to 110. 55%, and the RSDs were lower than 5. 43%. The results showed that the method had the advantages of fast, efficient, accurate and environmental protection. It provided a strong basis for the extraction, enrich. ment and analysis of the trace bio-active chemical composition of the traditional Chinese medicine and its preparations.