To explore the optimal planting density and nitrogen level for paddy-tobacco in South Hunan, the effects of planting density, nitrogen level and their interaction on economic character of flue-cured tobacco were analyzed by construction of economic character index and partial (Eta)2 value from two factors experiment. The results showed: 1) Planting densities, nitrogen levels and its interactions had different influence on flue-cured tobacco economic characters; planting density showed significant effect on the fine tobacco ratio and average price; planting densities, nitrogen levels and its interactions showed significant effect on the yield and out-put value of flue-cured tobacco. 2) The effect of planting density on the flue-cured tobacco economic characters accounted for 40% while the effect ofnitrogen levels and planting density-nitrogen level interactions on the flue-cured tobacco economic characters each accounted for 30%. 3) Economic character of flue-cured tobacco under treatment with 18 195 plant/hm2 was good was, economic character of flue-cured tobacco under treatment with N 165 kg/hm2 was good. 4) Economic characters of flue-cured tobacco was the best in treatment with 18 195 plants/hm2 combined with 142.5 kg/hm2 N.