The invention discloses a method for extracting chestnut flower volatile substances by using a supercritical CO2 fluid. The method comprises the following steps of: picking fresh chestnut flowers at a full-bloom stage; drying at a low temperature; smashing; storing at a low temperature; adding into an extraction kettle; connecting a CO2 supercritical extracting instrument; adjusting the pressure and temperature of the extraction kettle; extracting in a static state; turning static extraction into dynamic extraction; simultaneously, raising the pressure and the temperature of the extraction kettle; and collecting an extract in a dynamic extracting process, wherein an extract product is a yellow-green oily substance. In the method, volatile substances in chestnut flowers are extracted by using a supercritical CO2 fluid extracting technology, and extracting conditions are changed alternatively through a programmed temperature raising and programmed pressure raising method for extracting and collecting chestnut flower volatile substances. In the method, chestnut flowers are taken as a raw material; the extraction method has the characteristics of rapidness, easiness, convenience, environment friendliness, high efficiency and the like; and the extracted chestnut flower volatile substances can be applied to plant protection, medical and functional foods.