The experiment was carried to study the effect of combined application of tobacco stalk biochar and chemical fertilizer on the economic traits and agronomic characters of flue-cured tobacco，in order to determine the suitable application rate of tobacco stalk biochar in tobacco field.During April to August 2018，a field experiment was set up in Yuxi City，Yunnan Province，which was a two-factor experiment，including four biochar levels and three nitrogen fertilizer levels to study the effects on economic characters，agronomic traits，diseases and pests of flue-cured tobacco with different amounts of biochar and chemical fertilizer combined application.(1)The yield of tobacco showed an increasing trend with increasing fertilizer application rates，and compared with no chemical fertilizer，the application of 96 and 120 kg·hm-2 chemical fertilizers increased tobacco yield by 26.82% and 32.91%，respectively.The yield of tobacco increased first and then decreased with increasing biochar rates.When the rate of biochar was 6000 kg·hm-2，the yield of tobacco reached its maximum value.After that，when the rate of biochar increased，the yield of tobacco decreased rapidly.(2)The application rate of fertilizer，biochar and their interactions all had significant effects on the plant height，maximum leaf length，and maximum leaf area of tobacco in rosette stage，vigorous growing stage and capping stage(P<0.05).The yield of tobacco with the combined application of 6000 kg·hm-2 biochar and 120 kg·hm-2 fertilizer reached the highest，2346.21 kg·hm-2，and the ratio of upper-middle grade leaves reached 100%.The yield of 3000 kg·hm-2 biochar and 96 kg·hm-2 fertilizer was the second highest，2132.96 kg·hm-2，and the ratio of upper grade leaves reached 41.97%.(3)Appropriate application of chemical fertilizer could reduce the incidence and disease index of tobacco black shank，reduce the beetle plant rate and the yellow worm plant rate in the tobacco vigorous growing stage.Application of proper amount of biochar (3000 kg·hm-2)could inhibit the diseased plant rate and disease index of black shank in the tobacco vigorous growing stage and the capping stage，and reduce the beetle plant rate and the yellow worm plant rate in the tobacco rosette stage.These results show that appropriate application of tobacco stalk biochar and chemical fertilizer can improve the yield and quality of tobacco，and promote the green development of agriculture.