[Objective]This study aimed to compare the effects of low-temperature low-humidity tobacco flue-curing technology,moderate-temperature moderatehumidity tobacco flue-curing technology and moderate-temperature high-humidity tobacco flue-curing technology on submicroscopic structure of flue-cured tobacco leaves to provide theoretical basis for tobacco flue-curing. [Method] Middle leaves of tobacco cultivar K326 were collected in Pengshui County of Chongqing City for flue-curing experiment using three flue-curing technologies. Leaf samples were collected regularly in the flue-curing process,to investigate the submicroscopic structure of flue-cured tobacco leaves. [Result]Morphology changes and structural rupture of chloroplasts occurred at different time during three flue-curing processes. In low-temperature low-humidity flue-curing process,morphology changes and structural rupture of chloroplasts occurred late but rapidly; in moderate-temperature moderate-humidity flue-curing process and moderate-temperature high-humidity flue-curing process,morphology changes and structural rupture of chloroplasts occurred early but slowly. Among these three flue-curing processes,the speed of changes in mitochondria morphology,cristae number and membrane rupture presented an upward order of low-temperature low-humidity flue-curing process < moderate-temperature high-humidity flue-curing process < moderate-temperature moderate-humidity flue-curing process. In low-temperature low-humidity flue-curing process,starch granules in chloroplasts ruptured after flue-curing for 36- 48 h;in moderate-temperature moderate-humidity flue-curing process,starch granules in chloroplasts ruptured after flue-curing for 24- 36 h; in moderate-temperature high-humidity flue-curing process,starch granules in chloroplasts ruptured after flue-curing for 12- 24 h. [Conclusion]Using low-temperature low-humidity fluecuring technology could prolong the maintenance duration of the submicroscopic structure integrity of flue-cured tobacco leaves,which was conducive to fully decomposing and transforming substances in tobacco leaves and obtaining high-quality flue-cured tobacco leaves. [Objective] This study aimed to compare the effects of low-temperature low-humidity tobacco flue-curing technology, moderate-temperature moderate humidity tobacco flue-curing technology and moderate-temperature high-humidity tobacco flue-curing technology on submicroscopic structure of flue- cured tobacco leaves to provide theoretical basis for tobacco flue-curing. [Method] Middle leaves of tobacco cultivar K326 were collected in Pengshui County of Chongqing City for flue-curing experiment using three flue-curing technologies. Leaf samples were collected regularly in the flue [0191] [0191] Morphology changes and structural rupture of chloroplasts occurred at different time during three flue-curing processes. changes and structural rupture of chloroplasts occurred late but rapidly; in moderate-temperature moderate-humidity flue-curing process and Moderate-temperature high-humidity flue-curing process, morphology changes and structural rupture of chloroplasts occurred early but slowly. Among these three flue-curing processes, the speed of changes in mitochondria morphology, cristae number and membrane rupture presented an upward order of low -temperature low-humidity flue-curing process