To analyze the chemical composition and aroma composition of tobacco before and after expansion in order to develop a carbon dioxide expansion process for producing high-quality tobacco. The influence of different carbon expansion technology conditions on the physical processing quality and sensory quality of expanded tobacco was determined and the trend of change was determined by the single factor test method. After different temperature of carbon dioxide expansion, HT treatment and drying, the variation trend of tobacco aroma composition and sensory quality were basically the same, but the variation trend of tobacco aroma composition and sensory quality decreased more obviously after carbon dioxide expansion. The moisture content of tobacco after carbon dioxide expansion increased to some extent, which promoted the expansion effect of tobacco. The best expansion temperature of tobacco carbon dioxide was 250 ℃, further confirming that the better soaking time of carbon dioxide was 120 s, and the filling value of tobacco was 6.8 cm3/g.