Abstract: The volatile oil extracted from dried leaves of Vitex negundo var. heterophylla Rehd. was determinated by gas chromatography-mass spectrometry (GC/MS). Thre results showed thirty-six constituents in sample have been separated. Among which, the chemical structure and relative content of twenty-nine constituents were identified, the sum of their contents was 94. 68% of the total. The twenty-two constituents assigned to ter-penoids and their derivatives make up 89. 13% of the total volatile substances. The main component was β-Caryophyllene making up 48. 70% of the total, β-Farnesene making up 15.52%.