The invention discloses a reagent for preventing and treating tobacco wildfire and a preparation method thereof. The reagent comprises the following components: benziothiazolinone, copper abietate, kasugamycin, zinc thiazole and oxine-copper. The reagent prepared by the method of the invention not only has a good prevention and treatment effect on tobacco wildfire, but also can delay the generation of drug resistance, and does not pollute the soil environment at the same time.