The invention provides a botanical compound insecticide for prevention and treatment of beet armyworm. The botanical compound insecticide is characterized by comprising the following components in terms of each 1 L of the insecticide: 0.42 to 1.67 g of a n-butyl alcohol phase extract of Chinese magnoliavine fruits, 0.42 to 1.67 g of a n-butyl alcohol phase extract of Tragus berteronianus, 0.42 to1.67 g of a n-butyl alcohol phase extract of Celastrus orbiculatus and 100 mL of an auxiliary solvent, with the balance being distilled water. The botanical compound insecticide provided by the invention has the following advantages: the botanical compound insecticide has significant insecticidal effect on beet armyworm larvae; meanwhile, the constitution raw materials of the botanical compound insecticide provided by the invention are non-chemical agents and have little harm to the environment; pests are insusceptible to generating insecticide resistance; and the botanical compound insecticide is green and environmentally-friendly.