Abstract: The effects of organic fertilizer(cake fertilizer) and sulfer fertilizer(K2SO4) applications on flue-cured tobacco quality were studied by using the orthogonal-gyrating regression. Basing on two quality indices (the ratio of nitrogen to nicotine, the ratio of reducing sugar to nicotine), a mathematical model was established of the significant relationship between leaf quality and the fertilization rate of organic fertilizer (rapeseed cake) and sulfer fertilizer (K2SO4). Through variance analysis and optimizing simulation, the optimum rates for balanced application were organic fertilizer at medium to low level of 300-375 kg/ha and sulfer fertilizer at medium level of 56.25 kg/ha. In conclusion, it is not appropriate to apply excess sulfer, and the main effecting factor of flue-curd tobacco quality is organic fertilizer ( rapeseed cake).