Method for extracting evodine from seed or fruit of rutaceous plant

The invention discloses a method for preparing evodine by using a seed or a fruit of a rutaceous plant as a raw material. The method comprises the following specific steps: adding a solvent into dried raw material powder for extraction, and recovering the solvent to obtain an extract; performing degreasing through petroleum ether, and performing washing through an acid solution; dissolving a residual solid by using a sodium hydroxide solution or a potassium hydroxide solution, and performing filtration or centrifugation to obtain an alkali solution; adjusting pH through hydrochloric acid, and separating a solid out; dissolving the solid through chloroform or dichloromethane, performing filtration or centrifugation, and recovering the solvent to obtain a solid; washing the obtained solid by using a small amount of methyl alcohol, ethyl alcohol, chloroform, methane, dichloromethane or acetone, dissolving the solid by using the dichloromethane, the chloroform or the acetone, performing crystallization, and then performing re-crystallization by using the dichloromethane, the chloroform, the acetone, the ethyl alcohol, isopropyl alcohol or a mixed solvent thereof to obtain high-purity evodine finally. The evodine (limonin) prepared by using the method is high in purity, low in cost, simple in operation, high in yield, and easy to apply to industrial production on a large scale.