Nitrogen uptake of different parts of flue-cured tobacco under different fertility condition by using 15N tracer technique was studied. Results showed that flue-cured tobacco took up more N from soil than from N fertilizer, and 18.67%-29.32% of N absorbed by flue-cured tobacco was derived from N fertilizer, 70.68%-81.33% from soil under two level fertility fields. Compared with the higher fertility field, the amount of fertilizer N and soil N absorbed by flue-cured tobacco was higher at the earlier stage. But there were the reverse trends at the midterm and late stage. During the maturity, the nitrogen accumulation amounts and distribution proportion of stem increased and the nitrogen accumulation amounts and distribution proportion of leaves decreased. The distribution proportion increasing extent of stem and decreasing extent of leaves were higher in higher soil fertility than in lower soil fertility. The nitrogen utilization efficiency (NUE) under lower fertility field was from 8.81% to 11.20%, and the NUE under higher fertility field was from 3.00% to 16.76%.