Abstract: In order to explore the relationship between nitrogen and nicotine accumulation, we used sand and solution culture to study the interaction effects of nitrogen supply and axillary bud growth on the accumulation of nicotine and IAA in flue-cured tobacco. The results showed that sucker control could stimulate tobacco to synthesize nicotine even without nitrogen supply and nicotine accumulation increased with nitrogen supply. With the growth of axillary bud, the IAA increased, while the synthesis of nicotine was inhibited. Under the no-nitrogen condition, nicotine was broken down to meet the needs of axillary bud growth. Interaction effect analysis showed that axillary bud affected the nicotine accumulation and IAA more significantly than did nitrogen. In conclusion, tobacco can use the accumulated and absorbed nitrogen to synthesize nicotine and axillary bud is not conducive to the accumulation of nicotine.