The invention discloses a tobacco strong seedling resistance inducer which is composed of, by mass components, uniconazole, calcium salicylate, diethylaminoethyl hexanoate, sodium nitrophenolate, chitooligosaccharide, Tween, dimethyl sulfoxide, ascorbic acid, prohexadione-calcium, 5-aminolevulinic acid, potassium phosphite, glycine, boric acid, zinc sulfate, copper sulfate, ammonium molybdate, xylitol, and the balance water. By applying the tobacco strong seedling resistance inducer for flue-cured tobacco floating seedling growing production, the low temperature resistance at the seedling stage can be enhanced, the effect of promoting robust growth of tobacco seedlings is achieved, the total root length, the total root surface area, the total root volume of the tobacco seedlings before transplanting are remarkably improved, and the accumulation and root cap ratio of tobacco seedling overground parts and root system dry substances are remarkably improved, the growth of flue-cured tobacco in a field period is promoted, and the tobacco plant biomass and yield and quality after tobacco leaf curing are significantly improved, thereby improving the social and economic benefits of tobaccoproduction.