Abstract: [Objective and Method]In this study β-glucuronidase gene (GUS) was used as reporter gene in biolistic transformation experiment. Transient expression vector of cotton GhCAD6 gene was constructed. [Result]Firstly, the GhCAD6 gene cDNA was obtained from pGEM-T-CAD6 by PCR, then it was cloned into transient expression vector pRTL2-GUS/NIa. The transient expression vector pGUS-CAD6 is driven by CaMV35S promoter with GUS reporter gene and the target gene, GUS reporter gene and target gene simultaneously express in single cell. Secondly, verified by digestion with restriction enzymes, the vector pGUS-CAD6 was transformed into onion using PDS-1000/He biolistic particle delivery system. The GUS gene expression was detected in 24 h after bombardment,strong GUS gene expression was observed in the epidermal cells of onion under microscope, the results indicated that the transient expression vector pGUS-CAD6 could be highly effectively expressed in plant cell. [Conclusion]The results of this paper provide a strong foundation for analyzing function of GhCAD6 gene in cotton in the future.