The invention discloses a breviscapin-containing oral cavity spraying agent, which is mainly prepared from the following components in percentage by mass: 5 to 10 percent of breviscapin, 3 to 6 percent of cosolvent, 0.1 to 1.5 percent of sorbefacient, 0.1 to 0.3 percent of preservative, 0.02 to 0.08 percent of flavoring agent and the balance of purified water. A preparation method of the oral cavity spraying agent comprises the following steps of: crushing the breviscapin, adding ethanol, heating for refluxing, and filtering and concentrating; after heating, regulating the pH value, standing, filtering, regulating the pH value of filter liquor, standing and performing suction filtration; precipitating with ethanol and washing with the water; adding methanol and active carbon, heating, filtering, concentrating the filter liquor, crystallizing, and washing and drying to obtain a coarse product; regulating the pH value of the coarse product, heating, centrifuging, allowing the filter liquor to pass through resin, eluting, concentrating the filter liquor under reduced pressure, performing suction filtration, regulating the pH value, standing and performing suction filtration to obtain precipitates, and washing and drying to obtain the breviscapin; and dissolving the breviscapin in the components, stirring uniformly, and filtering to obtain the spraying agent. The oral cavity spraying agent has quick response, high bioavailability and good effect of treating cardiovascular and cerebrovascular diseases, and is convenient to carry.