Abstract: Taking cultivar Dabai No.1 as the sample,the effects of nitrogen rate and basal fertilizer/dressing ratio on the contents of chemical and aroma components in burley tobacco were investigated in Dazhou,Sichuan.The results showed that nitrogen rate and basal fertilizer/dressing ratio affected chemical and neutral aroma components differently.The contents of total nitrogen,nicotine,K⁺+and K⁺+to Cl^-ratio in burley tobacco increased,while total sugar,reducing sugar, Cl^- and total nitrogen to nicotine ratio decreased along with the increase of nitrogen application amount.The contents of total neutral aroma components in middle leaves of all treatments increased first and then decreased somewhat with the increase of nitrogen rate.For the treatments of lower N rate(120 to 255 kg/hm²),increasing dressing proportion could raise the total amount of neutral aroma components;while for the treatments of higher N rate(300 kg/hm²),basal fertilizer/dressing ratio possessed little effects on the total amount of neutral aroma components.When nitrogen rate was higher than 255 kg/hm²,the total nitrogen and nicotine contents would be too high to maintain chemical balance in tobacco.Under the same nitrogen rate within 0 to 210 kg/hm²,total nitrogen,nicotine,K⁺+,and K⁺+to Cl^-ratio increased with the decrease of basal fertilizer proportion.When nitrogen rate exceeded 255 kg/hm²,the influence of basal fertilizer/dressing ratio on the contents of total nitrogen and nicotine was not obvious.In view of chemical and neutral aroma components,the optimal treatment was pure nitrogen rate within 210 to 255 kg/hm² and basal fertilizer proportion 60%.