Abstract: After inducement of IPTG, the recombinant protein of mud carp growth hormone (mcGH) was expressed in Escherichia coli. SDS-PAGE electrophoresis showed that there was a band of about 24.5 kDa, which size was similar to the predicted mcGH. After purification and renaturation, the recombiant mcGH was used as an antigen to inoculate the rabbit. The titer of the obtained antiserum was determined to be 1 : 12 800 by indirect enzyme-linked immunosorbent assay (ELISA).Immunochemistry analysis showed that the antiserum could detect the antigen as low as 10 ng. Furthermore, western blotting analysis showed that 21.5 kDa protein in mud carp pituitary and serum could be detected using the primary antibody. These results showed that the polyclonal antiserum of rabbit anti-mcGH was effective and highly specific.