The invention discloses botanical insecticide and a preparation method thereof. The botanical insecticide comprises the following raw materials in parts by weight: 65 to 76 parts of toosendanin original liquid, 2 to 5.2 parts of
croton oil original liquid, 4.5 to 7 parts of
limonene original liquid, 8 to 13 parts of
dimethyl sulfoxide, 4.5 to 10 parts of organic
silicon surfactant and 0.4 to 0.8 part of
plant emulsifier. The preparation method comprises the following steps: S1, weighing the toosendanin original liquid, the
croton oil original liquid, the
limonene original liquid, the dimethylsulfoxide, the organic
silicon surfactant and the
plant emulsifier according to the formula quantity; S2, adding the toosendanin original liquid, the
croton oil original liquid and the
limonene original liquid weighed in the step S1 into an emulsifying
machine, slowly adding the organic
silicon surfactant and the
plant emulsifier in the emulsification process, and stirring and emulsifying for 15 to 30 minutes to obtain the botanical insecticide. The botanical insecticide provided by the invention has efficient broad-spectrum insecticidal and antibacterial effects, significant insecticidal effect and
low toxicity, can be naturally degraded and avoids residue.