Abstract:The material is ‘Xinluzao 36’ transformed with GhCAD6 gene obtained by Agrobacteriummediated transformation. In this study, the T6 generation of the transgenic material was used as experimental material. The integration of GhCAD6 gene in the genome of cotton, the expression in different developmental stages of cotton fiber, the content of structural polysaccharides and phenylpropanoid compounds in the cotton fiber, and the influence of the fiber in the phenylpropanoid monomer were analyzed. The results showed: (1) GhCAD6 was integrated in the form of single copy to the recipient cotton genome. (2) The expression level of GhCAD6 in the transgenic plants was lower than that in the control samples at the same developmental stage. The expression of GhCAD6 was increased firstly, reached the highest at 20 DPA and then decreased in the control samples. While the expression decreased at 15 DPA in the transgenic plant fibers, rose to the highest level at 20 DPA, and then decreased. (3) In mature fibers, the content of phenylpropanoid compounds in the transgenic plants was lower than that in the control samples, and the content of structural polysaccharides had no significant difference. (4) The ratio of S/G decreased in cotton fiber of transgenic plants. After the GhCAD6 gene transferred into cotton, the change of GhCAD6 gene expression at 15 DPA may be the cause of the change of content of phenylpropanoid compounds and ratio of structural monomer, which result in the variation of cotton fiber quality. The results of this research can provide theoretical basis for further analysis of the mechanism of GhCAD6 gene in improving cotton fiber quality.