Abstract: To investigate the effects of biochar on the quality improvement of tobacco planting soil and tobacco production, a field experiment with 5 treatments: T0, 0 t/hm² biochar+0.64 t/hm² nitrogen fertilizer; T1, 0.5 t/hm² biochar+0.64 t/hm² nitrogen fertilizer; T2, 1 t/hm² biochar+0.64 t/hm² nitrogen fertilizer; T3, 1.5 t/hm² biochar+0.64 t/hm² nitrogen fertilizer; T4, 2 t/hm² biochar+0.64 t/hm² nitrogen fertilizer was conducted. The effects of biochar on the carbon emission and organic carbon components of tobacco planting soils and tobacco physiological indexes were analyzed. The results showed that: 1) Compared with treatment T0, treatments T1, T2 and T3 reduced the total soil carbon emission by 28.14%, 25.25% and 8.41% respectively; and treatment T4 raised the total soil carbon emission by 8.79%. 2) The biochar treatments increased the contents (mass fractions) of soil total organic carbon, microbial biomass carbon, soluble organic carbon and easily oxidized organic carbon. On the 70th day after transplanting, the total organic carbon and microbial biomass carbon in soils of treatment T4 were 19.38% and 29.38% higher than those of treatment T0. The proportion of microbial biomass carbon in total organic carbon decreased, while the proportion of soluble organic carbon in total organic carbon increased with the application of biochar. 3) The biochar treatments promoted tobacco root vigor, the photosynthetic characteristics of tobacco leaves and the dry matter accumulation in tobacco plants. Among them, treatment T3 increased tobacco root vigor by 80.43% comparing with treatment T0. Therefore, suitable biochar applications can reduce soil carbon emission, increase contents of different soil carbon components, promote the root growth and development, photosynthetic characteristics and dry matter accumulation of tobacco plants.