Abstract: 【Objective】To improve the quality of the flue cured tobacco leaf by combined application of chelated fertilizer. 【Method】Effects of combined application of chelated fertilizer on the contents of total sugar, reducing sugar, total nitrogen, nicotine and potassium of flue-cured tobacco leaf were studied using the pot and field experiments. Effects of chelated fertilizer of Kangkai Ⅱ, Funuogen, Funuo potassium or Funuo phosphorus on the quality of tobacco leaf were analysed. 【Result and conclusion】The results showed that in plot experiments, application of Kangkai Ⅱ and Funuogen at the stage of seedling, Funuo potassium or Funuo phosphorus at the stage of growing reduced the contents of tobacco leaf nicotine by 42.86% and 26.02% and increased the potassium contents by 41.24% and 3.44%. In field experiments, The combined application of Kangkai Ⅱ, Funuogen, Funuo potassium or Funuo phosphorus reduced the contents of tobacco leaf nicotine by 56.00% and 93.28%, increasing the potassium contents by 23.11% and 29.25%,respectively.