The N protein, E protein and S protein antigens of the novel coronavirus can be used as immunogens to stimulate plasma cells to produce specific antibodies after the virus infects the human body. According to the principle of double-antibody sandwich ELISA, the sample drops were added to the sample pad and passed through the bonding pad, the detection line (T line) and the quality control line (C line) on the NC film by liquid chromatography in turn. The binding pad contains labeled antigen-specific antibodies that can bind to the antigen (viral protein) in the sample.