The invention discloses an intensive culture fry insecticide for controlling cybister sharp and a preparation method thereof. The insecticide comprises, by weight, 10-15 parts of pomegranate peel, 5-10 parts of cyrtomium rhizome, 5-10 parts of Chinese gall, 5-11 parts of radix asparagi, 5-10 parts of ash bark, 10-15 parts of lygodium japonicum, 3-8 parts of cassia bark, 5-8 parts of solanum vine,3-5 parts of serissa herb and 6-12 parts of pyracantha fortuneana fruit. In the formula, pomegranate peel, Chinese gall, lygodium japonicum and pyracantha fortuneana fruit serve as monarch ingredients, radix asparagi, ash bark and cyrtomium rhizome serve as ministerial ingredients and assist the monarch ingredients in coming into play, cassia bark and solanum vine serve as adjuvant ingredients, and serissa herb coordinating the ingredient actions serves as a conductant ingredient. The insecticide is prepared from pure natural Chinese herbs, has a wide raw material source and has no bad effecton the growth of fry, all the ingredients are used in cooperation, have a synergic effect and can effectively kill cybister sharp in water to avoid the influence of cybister sharp on the growth of fry, and the insecticide has a high application and popularization value and provides valuable guidance for the intensive culture of fry.