【Objective】 The differences of metabolites in cigar tobacco fermented in summer and winter were analyzed. 【Method】 Widely targeted metabolomics detection（UPLC-ESI-MS/MS）was used in combination with multivariate statistical analysis（PCA and OPLS-DA）. 【Result】 During the fermentation period（lasting for 34 d）, the average temperature of the fermentation room in summer and winter were 27.2℃ and 14.7℃, respectively, with a difference of 12.5℃, and the average humidity was 77.6% and 66.7%, respectively, with a difference of 10.9%, thus summer was more in line with the environmental requirements of relatively high temperature and high humidity for tobacco fermentation. A total of 905 metabolites were detected in cigar leaf samples, including alkaloids, phenolic acids, flavonoids, lipids, amino acids, organic acids, terpenes, sugars, nucleotides, and lignin. The top three metabolites were alkaloids, organic acids, and lipids, accounting for 24.5%, 23.7%, and 15.0%, respectively. After the fermentation, the contents of organic acids, lipids, amino acids and phenolic acids significantly increased, and the contents of alkaloids, terpenes, flavonoids, sugars and lignin decreased to varying degrees. In summer fermented tobacco leaves, the metabolic transformation of alkaloids and terpenoids was more intense, the contents of organic acids, amino acids, flavonoids, lipids and sugars were higher, the chemical composition was more coordinated, the aroma quality was richer, the flue gas was soft, the aftertaste was sweet, and the sensory quality was better.【Conclusion】 The natural high temperature and high humidity environment in summer in southwest Hubei is more suitable for the ideal state of cigar tobacco agricultural fermentation. The cigar leaves produced in the current year should be naturally aged in winter and then fermented in the next summer, which may be used as a reference scheme to explore and promote the quality and efficiency of the fermentation process of cigar.
