In order to clarify the changes and correlation between non-structural carbohydrates and plastid pigments in cigar tobacco leaves at yellowing stage under different air-curing processes. Taking Yunxue No.2 as the test material, the changes of internal chemical components of cigar tobacco leaves in yellowing stage under different environmental humidity were set at the same temperature. The results showed that : ( 1 ) Under different air-curing processes, the contents of plastid pigment and starch in tobacco leaves showed a downward trend during air-curing, while the contents of glucose, fructose and sucrose showed an overall upward trend. ( 2 ) The degradation rate of chlorophyll content in tobacco leaves treated with high humidity was slow, but the degradation cycle was long, while the content of high humidity and medium humidity treatment tended to be low after 96 h of yellowing, and the change was not obvious. ( 3 ) The accumulation of glucose and fructose content in low humidity treatment increased significantly in the early stage of yellowing, and the increment was small after 144 h of yellowing, while the change trend of medium humidity and high humidity content was opposite to that of low humidity, and the increment was not obvious in the early stage of yellowing, but increased significantly after 144 h of yellowing ; the change trend of starch and sucrose content under different treatments was almost the same. ( 4 ) The results of correlation analysis showed that the changes of plastid pigment content and non-structural carbohydrate content reached significant or extremely significant levels during the air-curing process. In summary, both high and low humidity affected the process of air-curing of cigar tobacco leaves. Appropriate humidity promoted the degradation of plastid pigments and macromolecular sugars in tobacco leaves, which was conducive to the formation of high-quality cigar tobacco leaves.