Abstract: The suppressor of cytokine signaling 3 (SOCS3) regulates the immune response. Here, we cloned the SOCS3b gene and investigated their role and distribution of SOCS3s in grass carp (Ctenopharyngodon idella). Grass carp SOCS3b gene was 2126 bp in length, encoding 216 aa peptides. In adult fish, both orthologs were expressed in 11 tissues with slightly different among tissues. After Aerononas hydrophila injection, both SOCS3a and SOCS3b were significantly up-regulated in the liver, spleen, intestine and kidney tissues. These results suggested that SOCS3s may play important roles in tissue growth of grass carp and the modulation of bacteria-induced innate immune response. This study provides relevant reference for the follow-up study of the function of SOCS3s genes in grass carp.