In this work,we reported a new strategy to improve the nonlinear saturable absorption performance of magnetite (Fe3O4) nanoparticles (FONPs) via the compositional engineering with the Ti3C2 MXene in the near-infrared (NIR) region.Based on the DFT simulation,the band structures and work function were significantly modified by the Ti3C2 MXene doping.By using the open-aperture Z-scan technology,the nonlinear optical features of the FONPs@Ti3C2 nanocomposite were significantly improved,show-ing the great potential as the saturable absorber in the pulsed laser.With the nanocomposite as the saturable absorber,the passively Q-switched Nd∶GdVO4 lasers emitted much shorter pulse durations when compared with the pristine FONP saturable absorber.These findings indicated that FONPs@Ti3C2 heterostructure was a promising saturable absorber for the short pulse generation in the NIR region.