Abstract: In order to identify the effects of potassium (K) fertilization regulation on aroma constituents in flue-cured tobacco leave, a field experiment was conducted to study the changes of K rates and proportion of base K to dress K fertilizer on the neutral aroma constituents in middle and upper leaves of tobacco (cv. Yunyan 87). The results showed that the contents of the all neutral aroma constituents and every degradation products were different under the different potassium fertilization rates and ratios. Neutral aroma constituents in upper leaves increased with the higher potassium rate. The content of plastid pigment degradation products in upper leaves were the highest relatively under top dressing fertilizer of middle potassium level and low dressing fertilizer of high potassium level, while the non-plastid pigment degradation products was the highest under top dressing fertilizer of high potassium level. It was more conducive to the formation of neutral aroma constituents in middle leaves under top dressing fertilizer of low potassium level.