Colloidal gold for antigen detection refers to a new immunolabeling technique applied to antigen-antibody. The colloidal gold method for antigen detection is actually a colloidal gold immunization technique that uses an antigen-antibody reaction. If a patient is infected with a certain pathogen, the patient’s specimen is reacted with the corresponding antigen test paper and a positive result will appear. The current situation of the new crown epidemic, for high-risk areas or centralized isolation of the population, the antigen of the new coronavirus can be used for self-testing, which can screen out those patients who are suspected to be positive, so as to avoid going to centralized places to do nucleic acid. This avoids the risk of aggravating the risk of infection by crowd gathering. The colloidal gold method of antigen detection is a more widely used method of antigen detection, which can clarify the infection of the pathogen, and the operation is relatively simple.