The invention discloses application of a Luotonin A compound to prevention and treatment of green peach aphid, Chinese scholar tree aphid, hickory nut aphid and alfalfa aphid. The compound is high in aphid killing activity, can prevent and treat aphid harms and can serve as a new aphid-killing forerunner to be developed. Due to the fact that the compound is from a natural product of Chinese herbal medicine peganum nigellastrum bunge, the compound has the advantages of being free of pollution, safe and efficient, has the advantages of natural source pesticide and can serve as new potential forerunner molecules of plant source pesticide for producing green and pollution-free agricultural products.