The invention belongs to the fields of agriculture and the planting industry, and concretely relates to a tobacco additional fertilizer and an application method thereof. A technical problem to be solved in the invention is providing the tobacco additional fertilizer. The tobacco additional fertilizer mainly comprises N, P, K, B, Cl, Mg, Ca and S according to a weight ratio of 4.79:5.41:27.81:0.34:4.0-5.4:2.4:8.4:3.78. The application method of the tobacco additional fertilizer is characterized in that the tobacco additional fertilizer is applied surrounding flue-cured tobacco in a circulating manner in the film uncovering, boxing, cultivating and hilling process of the flue-cured tobacco in 20-25d after the flue-cured tobacco is transplanted. The tobacco additional fertilizer has the advantages of reduction of the incidences of brown spots and mosaic disease, and improvement of the output and the quality of flue-cured tobacco.