Objective: To study the volatile oil in one-year-old and two-year-old of Radix Angelicae Sinensis (RAS). Method: The volatile oil is obtained by steam distillation

their chemical constituents is analyzed by GC-MS. Result: The content of volatile oil was 1.042% in one-year-old of RAS

which was much higher than the content of volatile oil 0.664% in the two-year-old of RAS. And their color was completely different. The chemical composition of volatile oil was basically consistent. In one-year-old of RAS the content of ligustilide was 54.01%

while the content of ligustilide was 46.06% in the two-year-old of the RAS. In the two-year-old of RAS

the content of 1

4-cyclohexadiene-1

2-dicarboxylic anhydride and butylidene phthalide were 11.22% and 14.19%

significantly above the 2.49% and 7.02% in the one-year-old of RAS. Terpenes of one-year-old of RAS were 27.85%

markedly higher than the 12.58% from the two-year-old of the RAS. Conclusion: The one-year-old of RAS have certain development value in the extraction of the content of volatile oil.