The invention discloses a gene gBabc which is obtained from main antigen glycoprotein gB of infectious bovine rhinotracheitis virus. The gene can express fusion protein which is high in immunogen activity, and finally, the gene can make a colloidal gold immunochromatography test strip which is used for detecting an infectious bovine rhinotracheitis antibody. The target gene disclosed by the invention, through successful and efficient expression as well as separation and purification, can prepare fusion antigen protein gBF for detecting the infectious bovine rhinotracheitis antibody, and experiments prove that the fusion protein is high in antigenicity and immunocompetence; therefore, a colloidal gold immunochromatography for the infectious bovine rhinotracheitis antibody is established.