Objective: To analyze the volatile components in Hypericum perforatum from Hebei province. Method: The volatile oil was extracted by steam distillation method and its chemical constituents were analyzed and identified by gas chromatography-mass spectrometry (GC-MS) technology. Result: The 58 compounds were isolated and identified from the volatile oil of H. perforatum

representing 90.0% of the total amount of volatile oil. The main constituents were identified as linalool (14.66%)

4-methoxypropenylbenzene (6.89%)

benzeneacetaldehyde (4.66%)

mushroom alcohol (4.41%)

and viridiflorol (4.38%). Conclusion: The volatile oil of H. perforatum from Hebei province was significantly different from that grown in other areas

indicating that the chemical constituents could be greatly influenced by various geographical locations and environmental conditions. It provides foundation for the rational development and utilization of this plant.