The invention relates to a tobacco aromatic substance and a preparation method and application thereof, and belongs to the technical field of tobacco essences and perfumes. The method comprises the steps that polybasic alcohol and organic acid-metal salt combination are added to a tobacco powder raw material, stirred and uniformly mixed, and reaction is conducted for 0.5-3 hours at the temperatureof 150-250 DEG C; obtained products are added to an organic solvent, after ultrasound extraction is conducted for 10-16 minutes, oscillation extraction is conducted for 10-60 minutes, centrifugal separation is conducted, after upper layer liquid is filtered by adopting an organic filtering membrane, pressure reduction distillation is conducted on filtered liquid to remove the organic solvent, andthe tobacco roasting aromatic substance is obtained. The tobacco roasting aromatic substance is compounded with isosorbide and applied to tobacco materials, the moisturizing maintaining property of the materials and the comfort and coordination of cigarettes can be effectively improved, and the tobacco aromatic substance is easy to be popularized and applied.