Current and residual effects of Mg, Cl and B and their interactions on flue-cured tobacco agronomic characteristics and economic characteristics were investigated through two years’ pot experiment. The results showed that B applied-alone increased tobacco output value significantly than Mg or Cl applied-alone, and the effect could be extended to the following year. Mg applied-alone also had positive effects. Both current and residual effects of Cl applied-alone on output value were not significant, whether applied Cl should be decided on soil Cl content and element interactions. 1︰1.51 was optimal ratio for Mg and Cl, which could promote tobacco growth especially in the current year and stimulated significantly the growth of middle leaves (length × width) and output value. Mg and B applied-together on the ration of 1︰0.08 had positive residual effects and it increased significantly tobacco output value. Cl and B applied-together on the ration of 1︰0.05 restrained tobacco growth in current year, but significantly increased the tobacco upper leaves length × width in the after-year, and increased tobacco growth, output value to some extent. In conclusion, reasonable fertilization should consider nutrient type, composite ratio, the interactions and residual effects.