The extraction method is: (1) steam distillation and water distillation, widely used in leaves, stems, dry, bark, seeds and roots of oil extraction, such as mint, cypress, cinnamon, vetiver, tracheid and so on. ② Press, cold grinding method, mainly used for sweet orange, lemon, lemon and other citrus fruit oil extraction. Because this method is not heated, the obtained essential oil aroma is fresh. ③ Solvent extraction method, mainly used for flowers, aromatic plant resin, spices processing. Volatile organic solvents used are petroleum ether, ethanol, acetone, etc., depending on different raw materials and selected. Since the flowers after the leaching solution, the material obtained after the removal of the solvent is called the extract, such as jasmine extract, brandy extract, etc. If obtained from the resin class is called incense resin, such as parsnip resin, benzoin resin, etc.; Get from spices, then say oleoresin, such as capsicum oleoresin, celery rapeseed oleoresin and so on. Due to the high wax content and poor solubility of the extract, ethanol is commonly used to put forward the alcohol-soluble flavor components, filter out the insoluble wax, and finally decompression steam to get ethanol, and get a net oil. The technology of liquid butane, carbon dioxide and supercritical fluid extraction is a relatively new technology, which can only be used in a few spice plants.