In order to reduce the application rate of nitrogen fertilizer in tobacco-rice rotation area and improve the yield and quality of tobacco(Nicotiana tabacum L.), using Yunyan87 as the material, 7 treatments including humic acid fertilizers(all-round organic carbon fertilizer and liquid organic carbon fertilizer) respectively with no nitrogen reduction, nitrogen reduction by 10%, nitrogen reduction by 20% and a blank control(CK) were designed to study the effects of different treatments on the agronomic characteristics, the accumulation of nitrogen, phosphorus and potassium, the physical and chemical properties of tobacco leaves, economic characteristics of tobacco, and on the partial factor productivity of nitrogen fertilizer. The results showed that the application of humic acid fertilizer could improve the agronomic characteristics(plant height and leaf number) of flue-cured tobacco, and liquid organic carbon fertilizer showed better growth improve effect compared to all-round organic carbon fertilizer. Nitrogen reduction could decrease dry matter accumulation, single leaf weight and leaf thickness, increase sugar content and decrease contents of nicotine and total nitrogen. Humic acid fertilizer application increased the accumulation and percentage of dry matter, increased the accumulation of nitrogen, phosphorus and potassium of tobacco leaves, increased the weight of single leaf, the sugar and potassium content of tobacco leaves, decreased the nicotine and chlorine content of the tobacco leaves, improve the proportion of high-quality tobacco, the yields, the output value, the nitrogen partial factor productivity and the nitrogen partial production efficiency. Compared to CK, the proportion of high-quality tobacco, yield, output value, nitrogen partial factor productivity and nitrogen partial production efficiency in treatment with all-round organic carbon fertilizer with 10% nitrogen reduction respectively increased by 4.04%, 6.54%, 10.12%, 27.89% and 32.15%; while the proportion of high-quality tobacco, yield, output value, nitrogen partial factor productivity and nitrogen partial production efficiency in treatment with liquid organic carbon fertilizer with 20% nitrogen reduction respectively increased by 15.33%, 2.87%, 9.38%, 28.16% and 36.71%. For the rice-tobacco rotation in Hunan province, it is recommended to apply all-round organic carbon fertilizer(45 kg/hm2) with 10% nitrogen reduction or apply liquid organic carbon fertilizer(75 kg/hm2) with 20% nitrogen reduction.