Objective To investigate the growth inhibition and DNA damage of energized fusion protein anti-CD20(Fab)-LDM on B JAB cells in vitro.Methods The binding activity of fusion protein anti-CD20 (Fab)-LDP to B JAB cells was studied by flow cytometry and confocal laser scanning microscopy.MTT assay was used to study the energized fusion protein anti-CD20(Fab)-LDM on cell growth of B JAB cells.Comet assay was employed to detect DNA damage in B JAB cells.The cell growth cycle of BJAB was analyzed by FACS.Results The recombinant fusion protein anti-CD20 (Fab)-LDP possessed an significant target affinity towarded BJAB cells.The energized fusion protein anti-CD20(Fab)-LDM showed obvious inhibition on proliferation,as well as induced potent DNA damage in B JAB cells in vitro compared with lidamycin.B JAB cells treated with energized fusion protein anti-CD20 (Fab)-LDM showed S phase cell cycle.Conclusion The energized fusion protein anti-CD20 (Fab)-LDM could target binding to BJAB cells and significantly inhibit the proliferation of B JAB cells by inducing DNA damage and S phase arrest.