Abstract: In order to promote early growth and rapid development of flue-cured tobacco in Chongqing, Yunyan 87 was used in this pot experimental study under illumination incubators to investigate the effects of root-promoting agents (Chitosan, NAA and IBA, Compound sodium nitrophenolate and sodium alginate, ABT, biological root-promoting agent, Agri-star soil-loosening root-promoting agent) on the growth of flue-cured tobacco shoots and roots, and the warming effect of biological root-promoting agents was verified by a field experiment. The results showed that T1 (Chitosan), T2 (NAA and IBA), T3 (Compound sodium nitrophenolate and sodium alginate), T4 (ABT) and T8 (Biological root-promoting agent made of oil cake, quicklime, biochar and starter) significantly promoted the plant height, stalk circumference, shoot dry matter accumulation, root length, root surface area and root volume of flue-cured tobacco grown at low temperatures. The promoting effects of T8 treatment on the development of flue-cured tobacco shoots and roots were the most significant and quite stable. Compared with the CK, the promoting effects of Agri-star soil-loosening root-promoting agent on the root number, root length, root surface area and root volume of flue-cured tobacco at low temperatures were the most significant, while its effects on the shoot growth were not obvious. T8 treatment could ensure the continuous warming effect of the soil tillage layer at seedling restoring stage and root extending stage of flue-cured tobacco with an increasing range of soil temperatures between 0.2 and 2.1℃. Therefore, this biological root-promoting agent was shown to be an effective means to promote the early growth and rapid development of flue-cured tobacco in Chongqing.