Abstract: 【Objective】 This study aimed to elucidate the physiological alterations and molecular mechanisms of tobacco in response to high temperature and drought stresses， providing theoretical basis for breeding tobacco varieties tolerant to high temperature and drought. 【Method】 Using the tobacco variety K326 as the experimental material，high temperature stress treatment （HS） and drought stress treatment （DS） were set in artificial climate incubator， and the tobaccos without high temperature or drought stress treatments were taken as control （CK） to determine psychological and biochemical indicators for transcriptomic and metabolomic analyses， thus exploring key metabolic pathways and genes in response to high temperature or drought stresses. 【Result】 Compared with CK， the relative electrical conductivity of tobacco leaves after drought treatment significantly increased （P<0.05， the same below）， while the malondialdehyde （MDA） content， proline content， and activities of antioxidant enzymes peroxidase （POD）， superoxide dismutase （SOD）， and catalase （CAT） extremely significantly increased （P<0.001）. Transcriptome data analysis revealed 21298 differentially expressed genes （DEGs） in the HS vs CK comparison group， in which 11251 were up-regulated and 10047 were down-regulated； 7673 DEGs were screened in the DS vs CK comparison group， in which 4462 were up-regulated and 3211 were down-regulated. Under high temperature and drought stress treatments， the up-regulated DEGs were significantly enriched in both flavonoid biosynthesis and galactose metabolism pathways， whereas the down-regulated DEGs were significantly enriched in both MAPK signaling pathway and phenylpropanoid biosynthesis pathway. Metabolome analysis revealed 152 differential metabolites （DMs） in the DS vs CK comparison group， in which 150 were up-regulated and 2 were down-regulated； there were 65 DMs both up-regulated under high temperature and drought stresses， among which the most abundant category was amino acids and their derivatives， followed by carbohydrates and their derivatives. Under high temperature and drought stresses， DMs commonly enriched in galactose metabolism， starch and sucrose metabolism， ABC transporters， and phenylpropanoid biosynthesis pathways. The integrated metabolomic and transcriptomic analysis indicated that under high temperature and drought stresses， DEGs and DMs commonly enriched in galactose metabolism and carotenoid biosynthesis pathways， in which the relative expression of raffinose synthase gene （RAFS） and 9-cis-epoxycarotenoid dioxygenase gene （NCED） was significantly or extremely up-regulated （P<0.01，P<0.001）. 【Conclusion】 High temperature and drought stresses severely inhibit the growth and development processes of tobacco， exacerbate cell membrane damage， and simultaneously induce the enhancement of antioxidant enzyme activities and proline accumulation， thereby scavenging the excessively accumulated reactive oxygen （ROS） in plants. Under high temperature and drought stresses， DEGs and DMs are enriched in both galactose metabolism and carotenoid biosynthesis pathways. By up-regulating the relative expression of RAFS and NCED genes， the contents of raffinose and abscisic acid （ABA） in tobacco increase significantly， while stomatal aperture decreases， thereby maintaining cellular osmotic balance and water homeostasis， and ultimately enhancing the tolerance of plants to high temperature and drought stresses.