This study used Gossypium barbadense Xinhai 21 and Gossypium hirsutum ND203 as well as model plant Arabidopsis thaliana to explore the function of Gossypium barbadense GbHCT13 gene (GenBank accession number MW048849) in fiber development through transgenic and fluorescence quantitative detection methods. The results showed as follows: (1) the recombinant vector pCAMBIA3301GbHCT13 was successfully constructed, and 4 Arabidopsis T₃ transgenic plants with GbHCT13 gene were identified by Agrobacterium mediated transformation, herbicide resistance gene screening, and fluorescence quantitative detection. QRTPCR analysis showed that the expression of GbHCT13 gene in transgenic plants was significantly increased compared with that of wild type. (2) The transgenic Arabidopsis thaliana overexpression of GbHCT13 made the plant grow more vigorously than the wild type at the same period, and the plant shape, leaf number, moss number and stem surface fur number were different from the wild type. Histochemical analysis showed that compared with wildtype stem, the primary xylem of transgenic Arabidopsis thaliana grew more active, the ducts were thickened, and the cross section area of ductal cell wall in secondary xylem was larger, but the medulla cells had no significant changes. Overexpression of GbHCT13 changed lignin synthesis pathway genes in Arabidopsis to different extent, and CAD, CCoAOMT, PAL and 4CL were positively correlated with the expression of GbHCT13. (3) Through field screening and molecular identification, 3 transgenic cotton plants with GbHCT13 gene were successfully obtained. The cotton fiber elongation and fiber strength of GbHCT13 transgenic cotton increased. The silencing of GbHCT13 gene reduced the lignin content of cotton plants, the number of stem surface fur, the number of xylem vessel cells and the lignin deposition in the vessel cell wall, but the cotton plants did not have obvious dwarf phenomenon on the plant height. Moreover, the expression of CAD, CCoAOMT, CCR and PAL 4 genes in lignin synthesis pathway all showed a decreasing trend, indicating that the inhibition of GbHCT13 impeded the growth and metabolism of cotton and affected the initiation of fiber development. The results showed that GbHCT13 can affect lignin synthesis in cotton plants and regulate fiber growth and development, and its function is basically the same as that of GbHCT13 in model plant Arabidopsis thaliana.