The invention provides a composite pesticide for preventing tobacco diseases and belongs to the technical field of pesticides. The composite pesticide for preventing the tobacco disease comprises animal dung, sawdust, attapulgite powder, nitrogen phosphorus and potassium composite fertilizer, composite amino acid, ferrous sulfate, the dark brown part in the licorice root, Chinese herbaceous peony, clover, felwort and an insecticide. The insecticide is prepared from, by weight, 0.5-3 parts of wood vinegar, 2-6 parts of chitin, 0.5-5 parts of matrine, 5-15 parts of semen aesculi, 5-15 parts of Chinese mugwort, 3-7 parts of litchi peel, 3-7 parts of lemon peel, 3-7 parts of luffa peel, 3-7 parts of cinnamomum camphora leaves, 5-10 parts of rosemaries, 5-10 parts of fructus forsythiae and 5-10 parts of acorus calamus. All the raw materials have a synergistic effect, the obtained composite pesticide is high in fertility and remarkable in antibacterial capacity, the probability of the tobacco diseases is obviously reduced, and the pesticide is efficient and saves labor and time.