Abstract: By using the ¹⁵N technique,the effects of nitrogen application and remained leaves on the N uptake and nicotine content of flue-cured tobacco were studied.The results show that there are observable effects of different nitrogen applications and remained leaves on the tobacco’s growth,dry matter accumulation,N uptake and distribution,nicotine content.N uptake and distribution affect the nicotine content of tobacco,about half of the fertilizer nitrogen is distributed in the leaves of tobacco and mainly in higher position leaves of tobacco plant.Nitrogen nutrition affects the nicotine content of higher position leaves of tobacco,the control of the nitrogen application and remained leaves can decrease the nitrogen content of the higher position leaves,thus decreasing their nicotine content.