Abstract: The present invention is directed to a humanized BCMA single-chain variable fragment (scFv), comprising VH having the amino acid sequence of SEQ ID NO: 7 and VL having the amino acid sequence of SEQ ID NO: 8. The present invention is also directed to a BCMA chimeric antigen receptor fusion protein comprising from N-terminus to C-terminus: (i) a single-chain variable fragment (scFv) of the present invention, (ii) a transmembrane domain, (iii) at least one co-stimulatory domains, and (iv) an activating domain. This humanized BCMA-CAR-T cells have specific killing activity with secretion of cytokine IFN-? in CAR-T cells in vitro and in vivo.