Objective: To study the chemical constituents of volatile oil extracted from roots and stems of Bupleurum chinense cultivated in Gansu Province.Method: The volatile oil was extracted from different parts（roots and stems） of Bupleurum chinense with steam distillation method

and the chemical constituents were analyzed and identified by gas chromatography-mass spectrometry（GC-MS）.The relative content of each constituent was calculated by area normalization method.Result: The yield of extracted volatile oil from roots and stems of B.chinense was 0.04% and 0.01%

respectively.A total of 95 compounds were identified from the two parts

of which 52 from roots and 72 from stems.There were 29 common compounds in both parts and accounted for 61.29% and 53.54% of the total volatile oil

respectively.The major components of volatile oil from roots include hexanal（17.00%）

2-pentyl-furan（8.10%）

palmitic acid（6.71%）

5-（1-methylethyl）-2-methyl-phenol（6.65%）

thymol（5.23%）

heptanal（4.64%）

and etc.The major components of volatile oil from stems include n-hexadecanoic acid（10.79%）

3-methyl-4-isopropylphenol（8.31%）

carvacrol（6.19%）

hexanal（6.09%）

2-pentyl-furan（4.42%） and etc.Conclusion: There are big differences both in the kind and content of volatile oil from different parts of B.chinense cultivated in Gansu Province.The results can be taken as a basis for the further development and utilization of B.chinense.