Abstract: Changes of dry matter accumulation， enzymatic activity of flue\|cured tobacco， microbial biomass carbon （MBC） and soil organic carbon were studied at different growth stages to explore the effects of biochar and nitrogen fertilizer on tobacco growth and soil biological characteristics via a field experiment. It was shown that at N1 （22.5 kg·hm-2）， N2 （37.5 kg·hm-2） and N3 levels （52.5 kg·hm-2）， application of 2.4 t·hm-2 biochar remarkably improved dry matter accumulation in the middle and late growth stage of flue\|cured tobacco and utilization rate of nitrogen fertilizer after 90 d of transplanting， and the nitrogen utilization efficiency increased the most at low nitrogen level（N1）. For all 3 N levels， application of biochar restrained sucrase activity. Meanwhile， for N1 and N2 levels， application of biochar could significantly increase urease and catalase activity. Besides， application of 2.4 t·hm-2 biochar significantly increased MBC content in the late growth stage of flue\|cured tobacco at N1 and N2 levels. Application of biochar with nitrogen fertilizers could remarkably increase soil organic carbon content during the whole growth period of flue\|cured tobacco. In general， application of biochar and nitrogen fertilizer could improve soil biological characteristics and promote the growth of flue\|cured tobacco， and at a low nitrogen level， application of 2.4 t·hm-2 biochar exhibited a better effect.

Key words: biochar, nitrogen fertilizer, flue\, cured tobacco, dry matter accumulation, soil biological characteristics