The invention relates to the technical field of pesticides, and discloses application of KN (potassium niobate)-2 and a KN-2-containing compounded preparation in prevention and treatment of tobacco mosaic virus (TMV). The KN-2 can induce TMV to generate specific resistance to effectively prevent and control TMV; the KN-2-containing compounded preparation SKGM-7 is capable of effectively preventing the damage and loss of TMV; the compounded preparation is prepared from KN-2, a virus inhibitor and pleocidin zinc. With the adoption of the KN-2 or SKGM-7 compounded preparation, the TMV can be effectively prevented and treated, the tobacco output and quality can be greatly increased, and therefore, the economic benefit is increased.