The invention discloses a plant essential oil preparation capable of preventing and controlling aleyrodidae adult pests as well as a preparation method and application thereof. The preparation comprises the following components by weight percent content: 40-60% of plant essential oil, 5% of a cosolvent, 10-15% of an emulsifier, 1-3% of an antifreezing agent and the balance of a solvent. The preparation has a good control effect on aleyrodidae adult pests, such as aleurocanthus spiniferus, aleurocanthus woglumi ashby, trialeurodes vaporariorum, bemisia tabaci and dialeurodes citri, and is especially quite good in fast-acting property, the control efficiency can reach 90% or above 0.5 h after application, and the natural enemies of ladybird, and the like, are not killed and hurt; the preparation is used for preventing and controlling aleyrodidae adult pests, can be sprayed in large fields with a conventional sprayer, can be directly applied in a greenhouse with a thermal aerosol sprayer, can be used as an environment-friendly smoke agent of the thermal aerosol sprayer, and is simple in processing technology, various in application methods, efficient, safe and environment-friendly.