Abstract: To investigate the nitrogen balance of tobacco-planting soils in rainy regions, the absorption and utilization of nitrogen by flue-cured tobacco and the fate of fertilizer nitrogen in tobacco-planting soils were studied by ¹⁵N isotope tracer test under different rainfall conditions (900-1 100 mm) during tobacco growing season. The results showed that with the increase of nitrogen application rate, the absorption of fertilizer nitrogen increased, while nitrogen utilization efficiency decreased. And the residual fertilizer nitrogen in soils and fertilizer nitrogen loss by runoff, leakage and the other forms increased significantly. Within the nitrogen application rate of 90-150 kg/hm², the nitrogen utilization efficiency of flue-cured tobacco dropped from 31.38% to 21.68%, and the proportions of residual fertilizer nitrogen and fertilizer nitrogen loss by runoff, leakage and the other forms accounted for 27.65%-30.51%, 22.42%-25.79%, 12.09%-15.16% and 6.47%-10.29% of nitrogen application rate, respectively. The utilization efficiency of residual fertilizer nitrogen in soils by flue-cured tobacco was from 7.10% to 8.15% in the 2nd year. And the residual fertilizer nitrogen in soils and fertilizer nitrogen loss by runoff, leakage and the other forms still accounted for 8.89%-9.95%, 4.46%-4.68%, 5.73%-6.59% and 1.16%-1.37% of the original nitrogen application rate, respectively. Therefore, higher residual fertilizer nitrogen in soils and more fertilizer nitrogen loss by runoff and leakage are the main reasons causing the lower nitrogen utilization efficiency of flue-cured tobacco in rainy regions, and the appropriate control of nitrogen application rate and reduction of fertilizer nitrogen loss by runoff and leakage are the main ways to promote the nitrogen utilization efficiency of flue-cured tobacco.