【Objective】The study aimed to find the best proportion of earthworm cast and chemical fertilizer under the condition of keeping the total nitrogen application unchanged.【Method】In this study, the field experiment was carried out with the earthworm cast in combination with chemical fertilizer. The effects of different ratios of earthworm cast and chemical fertilizer on tobacco growth and quality were analyzed with no fertilizer treatment as control, including T1(purified fertilizer treatment), T2(chemical fertilizer∶ earthworm cast = 7∶3 treatment), T3(chemical fertilizer∶ earthworm cast = 5∶5 treatment), T4(chemical fertilizer∶ earthworm cast = 3∶7 treatment).【Result】Compared with CK treatment, the agronomic traits, biomass of roots and middle leaves, root activity, nutrient contents of middle leaves, key enzymes of carbon and nitrogen metabolism and chlorophyll of fertilizer treatments were all improved. The root biomass and middle leaf biomass of tobacco were increased at maturity stage after applying earthworm cast. Moreover, root activity, nutrient content, key enzymes of carbon and nitrogen metabolism and chlorophyll content of tobacco increased; Root biomass of T2 treatment also increased by 13.6 %, 23.5 % and 27.6 % respectively compared with T1, T3 and T4 treatment at maturity stage; leaf biomass of T2, T3 and T4 treatment increased by 12.5 %, 10.3 % and 4.9 % compared with T1 treatment at maturity stage. Root activity of T3 and T4 increased by 14.2 % and 17.6 % in mature stage, nitrate reductase activity, amylase activity and invertase activity in middle leaf increased by 43.4 %-79.6 %, 11.6 %-71.0 %, 21.5 %-37.4 % in mature stage, respectively, compared to T1 treatment, chemical composition and coordination as well as sensory quality of flue-cured tobacco improved after applying earthworm cast. The nicotine content of middle leaves was decreased. Total sugar to nicotine ratios, total nitrogen ratios, reducing sugar to total soluble sugarratios, potassium to chlorine ratios, potassium content and total nitrogen content were increased. While the chlorine content of upper leaves were decreased. The potassium content and potassium-chlorine ratios were also increased and the aftertaste increased. Furthermore, the impurities were decreased, the yield value per mu, the average price, the proportion of top-grade tobacco and the proportion of medium-topped tobacco were increased whereas the yield did not change significantly.【Conclusion】Fertilization can increase the biomass of root and leaf, improve the nutrient content of middle leaf, enhance the key enzyme activity of carbon and nitrogen metabolism, improve the smoking effect of tobacco sensory quality,also increase the output value of flue-cured tobacco. The growth condition and yield-quality of tobacco could be further improved by applying earthworm cast. The comprehensive performance of T2 treatment was better. [ABSTRACT FROM AUTHOR]