Abstract: OBJECTIVE To explore the relationship between the amino acid and nucleoside contents in Changii Radix with their growth years. METHODS Ultra-fast liquid chromatography and triple quadrupole-linear ion trap tandem mass spectrometry(UFLC-QTRAP-MS/MS) was used to determine the contents of amino acids and nucleosides in Changii Radix and the root barks of Changium smyrnioides with six different growth years, then principal component analysis(PCA) and hierarchical cluster analysis(HCA) were used to analyze the differences of these contents in different growth years and their representative components. The amino column(2.1 mm×100 mm, 1.7 μm) and the mobile phase with acetonitrile-0.2% formic acid were used for gradient elution. The flow rate was 0.4 mL·min^-1 while the column temperature was 30℃. Mass spectrometry was performed by positive electrospray ionization(ESI⁺) and multiple reaction monitoring(MRM) modes. RESULTS The highest content in Changii Radix was asparagine which had been proved to reduce phlegm and relieve cough, and this content in Changii Radix aged 2-3 was as the highest(2.97%), while that of samples aged above 3 was at the same level(1.77±0.048)%. The representative components in different growth years of Changii Radix were:asparaginase in 2-3 years, alanine and guanosine in 4-5 years and 9-15 years, guanosine and adenosine in 6-8 years, proline and arginine in 16-18 years, and finally methionine and aspartic acid in 19-20 years. The content of amino acids and nucleosides in the root barks of Changium smyrnioides decreased with increasing growth years. CONCLUSION Asparagine is one of the main functional ingredients in Changii Radix; based on the difference of representative amino acids and nucleosides, the growth period of Changii Radix can be roughly determined; the root barks of Changium smyrnioides contain the same amino acids and nucleosides as Changii Radix, which means the root barks can be exploited rather than discarded.