Secretory IgA (SIgA) antibodies in external secretions play an important role in mucosal immune response. Polymeric SIgA was advantageous over monomeric IgA (mIgA) and IgG in several aspects. To express secretory IgA antibody against H5N1 virus, we constructed the secretory component and immunoglobulin J expressing plasmids and co-transfected the plasmids into the Chinese hamster ovary cells (CHO) stably expressing immunoglobulin A. Then we used Zeocin to select the positive clone cells, monoclonal cells stably secreting SIgA was screened through fold dilution method at last. The SIgA antibody secreted from the CHO cells was confirmed by Western blotting, which demonstrated that we had got the complete SIgA molecular. The successful expression of this polymeric anti-H5N1 SIgA in CHO cells will contribute to the production of recombinant SIgA as a preventive agent for infectious disease control.