Abstract: A chimeric antigen receptor is provided, including an extracellular segment, including a single-chain antibody region binding to an antigen human CD19 and a hinge region, a trans-membrane segment, including a trans-membrane domain of human CD8? linked to the hinge region of the extracellular segment and embedded in cell membrane of T lymphocyte, and an intracellular segment, including an intracellular domain of human CD8?, an intracellular domain of molecule 4-1BB and an intracellular domain of CD3 ? chain. The single-chain antibody region includes a heavy-chain variable region and a light-chain variable region of the single-chain antibody, the hinge region includes an extracellular domain of human CD8 alpha (CD8?) of 55 amino acid residues and three alanine residues (AAA) located at the N-terminal of the extracellular domain of human CD8?, and the intracellular domain of human CD8? includes seven amino acid residues and linked to the trans-membrane domain of human CD8?.