The invention discloses an anti-HER2 chimeric antigen receptor, an encoding gene, a recombinant expression vector, a construction method of the recombinant expression vector, and an application. The anti-HER2 chimeric antigen receptor comprises CD8 leader chimeric receptor signal peptide, an HER2 single-chain antibody heavy chain VH, Optimal Linker C, an HER2 single-chain antibody light chain VL, a CD8 Hinge chimeric receptor hinge, a CD8 Transmembrane chimeric receptor transmembrane domain, a CD137 chimeric receptor co-stimulated factor and a TCR chimeric receptor T cell activating domain which are connected in series. Moreover, the invention discloses an encoding gene of the anti-HER2 chimeric antigen receptor, a recombinant expression vector, a construction method of the recombinant expression vector, and an application. Secretion of cell factors and an in-vitro killing effect of CAR-T cells are obviously improved, and the CAR-T cells have an outstanding clinical treatment effect.