Abstract: Ultrasonic assisted extraction and methods of HPLC were established to determine cytidine,uridine,adenine,guanosine and adenosine in Radix Codonopsis. The best extraction condition for Radix Codonopsis was20 times the amount of pure water to extract by ultrasonic for 60 min,and repeat it for 2 times. Samples were separated and determined by a Venusil MP C₁₈( 2)( 4.6 mm × 250 mm,5 μm) using methanol- water system as mobile phase.Flow rate was 1.0 m L·min⁽- 1),and detection wavelength for fingerprinting was 260 nm with 35 ℃ for column temperature.Mass concentration of 5 components had good linear relation with peak areas( R²> 0.9995).And average recovery rates were from 97.05% to 101.81% with RSD ≤ 3.01%.The contents of nucleosides in Radix Codonopsis from different producing areas were different. The contents of cytidine,uridine,adenine,guanosine,adenosine and total nucleosides in 18 samples were listed as the followings: 68.71 ~ 478.82,171.33 ~ 629.60,33.63 ~140.05,221.31~651.37,143.26~511.78 and 679.87~2011.67 μg / g.The method in this study was easily performed with good precision,stability and reproducibility,accurate and reliable,so it was suitable to simultaneously determine the 5 components of nucleosides and bases in Radix Codonopsis. This provide scientific basis for objectively recognizing material basis of pesticide effect of Radix Codonopsis and developing multi- index evaluation system.