A field experiment was conducted in tobacco-planting paddy soil in Liangshan of Sichuan Province to study the effects of different nitrogen levels on inorganic nitrogen supply dynamic, dry matter accumulation of tobacco, nitrogen absorption, distribution regularity of tobacco and tobacco quality. The results showed that: the effect of nitrogen fertilizer on soil inorganic nitrogen lasted 13 weeks after transplanting. Soil inorganic nitrogen concentration increased with the increase of nitrogen application amount, the supply peak of inorganic nitrogen appeared from 7 weeks and 13 weeks after transplanting under different treatments. The dry matter accumulations of tobacco plant with nitrogen application were significantly higher than that of no nitrogen treatment, indicating nitrogen can promote root growth. Nitrogen application significantly increased tobacco nitrogen content in growth period, especially in 9 – 11 weeks after transplanting, the tobacco plant nitrogen accumulation with nitrogen 75 kg/hm² was significantly higher than that with nitrogen 45 kg/hm², but little difference between 75 kg/hm² and 105 kg/hm². Comprehensive sensory evaluation showed 75 kg/hm² nitrogen is suitable for the tested paddy soil.