To investigate the function of the GhCOMT1 gene,the GhCOMT1 gene was insert into the pET-28a vector to construct fusion vector pET-28a-GhCOMT1,and transformed into E.coli BL21 (DE3) cells.The fusion protein could be induced by 0.2 mmol/L IPTG treatment for 12 h at 16℃,for 3 h at 30℃ or 37℃,but the recombinant proteins mainly appeared as inclusion bodies.The most high expression quantity was induced at 16℃ for 12 h.Then to dissolved inclusion body,SDS-PAGE analysis indicated that its molecular mass is about 39.748 kD,Western blotting analysis indicated that the His polyclonal antibody could specifically bound to purified His-GhCOMT1 fusion protein.The prokaryotic expression system of pET-28a-GhCOMT1 is successfully constructed.It can be used to the further application study on function of GhCOMT1.