In order to investigate the structural characteristics of the toll–like receptor gene 9 in Squaliobarbus curriculus (ScTLR9), as well as its expression feature on the immune response in case of GCRV infection, the full–length cDNA of gene ScTLR9 was cloned using RACE technology in the study, and the expression of ScTLR9 on immune response in GCRV infection was analyzed using real–time qPCR. The results showed that the full–length cDNA of ScTLR9 was 3 687 bp encoding with a polypeptide of 1 059 amino acid residues and containing 17 LRR domains. The ScTLR9 mRNA was expressed in all collected tissues, and the relative expression level in mesonephros and head kidney were higher than that in other tissues; Under GCRV infection, the expression of TLR9 were up–regulated in head kidney for barbel chub and grass carp, the relative expression level reached its peak in 12 h for ScTLR9 in head kidney of barbel chub. It was speculated that the gene ScTLR9 was more quickly on the immune response against GCRV invasion in toll–like receptor than that in grass carp, it played an important role on the response to GCRV infection.