Abstract: Revealing the biological function of DXR gene in Lavandula angustifolia will provide scientific basis for improving the character of lavender essential oil. Based on this, taking tobacco as an example, Agrobacterium-mediated DXR gene genetic transformation was carried out on tobacco, and 10 tobacco plants with DXR gene transfer were obtained. Their expression levels in different transgenic plants were determined by fluorescence quantitative technique, and the contents of terpenoid volatile substances in the leaves of transgenic plants were measured by GC-MS technique. This study provided a basis for elucidating the role of DXR gene in the metabolism of terpenoid compounds in Lavandula angustifolia.