The invention belongs to the technical field of gene engineering, and particularly relates to an anti-BCMA antigen CAR and an expression vector, a CAR cell and application thereof. The CAR comprises an antigen recognition region capable of recognizing a BCMA antigen, a hinge region, a transmembrane region and an intracellular signal domain. The antigen recognition region for recognizing the BCMA antigen is an anti-BCMA single-chain antibody, wherein the heavy-chain amino acid sequence of the antigen recognition region is shown as any one of SEQ ID NO: 1-5, and the light-chain amino acid sequence of the antigen recognition region is shown as any one of SEQ ID NO: 6-10. The CAR can be stably expressed in patient-derived T lymphocytes, has better capability of removing tumor cells, and can beused for adoptive cell therapy aiming at hematological malignancies in preparation of drugs for treating hematological malignancies. The anti-BCMA antigen CAR cell not only can effectively remove tumor target cells expressing the BCMA antigen, but also has no toxic effect on negative antigen, namely tumor cells not expressing the BCMA, so that the safety is very high.