Abstract: The invention discloses a “line elimination” immunochromatographic strip and its application in CRISPR nucleic acid detection. The invention provides a kit, including the following: 1) Immunochromatographic strip, the immunochromatographic strip includes a sample pad containing a colloidal gold-labeled antibody, an NC membrane containing a T line and a C line, and a absorbent pad in sequence in the flow direction of the sample; the T line is formed by streptavidin; the C line is formed by a secondary antibody of the colloidal gold-labeled antibody; 2) a CRISPR reaction system, the CRISPR reaction system includes a reporter RNA, a crRNA and a Cas protein; the Cas protein is the Cas protein in the class II type V or VI CRISPR system. The experiments of the invention have proved that by combining the CRISPR nucleic acid detection system, the strip in the kit can realize the detection of various specific nucleic acids (pathogens, genes mutations, drug resistance mutations, etc.