To investigate the feasibility of solid-state fermentation of low-grade tobacco leaves with Eurotium cristatum, E.cristatum was isolated from Fuzhuan tea and inoculated into low-grade tobacco leaves for solid-state fermentation.Simultaneous distillation extraction and GC/MS were used to detect the changes in the main aroma components of tobacco leaves at 1, 3, 5, 7 days during solid-state fermentation.Sensory evaluation was conducted to investigate the impact of solid-state fermentation time on tobacco quality.The candidate strain GT-1 was successfully isolated from Fuzhuan tea, and confirmed as E.cristatum by morphological and molecular identification.The results showed that the sensory quality of tobacco leaves was the best after fermentation for 5 days, and the aroma amount, concentration and aftertaste were significantly improved compared with untreated tobacco leaves.A total of 33 main aroma components were detected, including 16 carotenoid degradation products, 9 aromatic amino acid conversion products, 1 chlorophyll degradation product, 1 of cembranoid degradation products, and 6 Maillard reaction products.With the extension of solid-state fermentation time, the total amount of main aroma components in tobacco leaves shows a trend of increasing and then decreasing.The total amount of aroma components reaches its highest point at 402.03 μg/g on the 5th day.Compared to the CK, the content of aroma components increased by 22.54%.Among them, the content of aroma substances such as 4, 7, 9-macrostigmen-3-one, geranylacetone, dihydrokiwifruit lactone, benzyl alcohol, phenylethanol, and 2-acetylpyrrole were significantly increased, which greatly enriching the sweet, tobacco, fruit, flower aromas of the smoke.Solid-state fermentation with E.cristatum GT-1 can increase the content and variety of aromatic substances in tobacco leaves, and thus effectively improve the quality of low-grade tobacco leaves. [ABSTRACT FROM AUTHOR]