To modify the stable thermodynamics and poor kinetics of magnesium hydride (MgH₂) for solid-state hydrogen storage, MIL-100(Fe) was in situ fabricated on the surfaces of TiO₂ nano-sheets (NS) by a self-assembly method, and the prepared TiO₂ NS@MIL-100(Fe) presents an excellent catalytic effect on MgH₂. The MgH₂+ 7wt.%TiO₂ NS@MIL-100(Fe) composite can release hydrogen at 200 °C, achieving a decrease of 150 °C compared to pure MgH₂. Besides, the activation energy of dehydrogenation is decreased to 70.62 kJ/mol and 4 wt.% H₂ can be desorbed within 20 min at a low temperature of 235 °C. Under conditions of 100 °C and 3 MPa, MgH₂+7wt.%TiO₂ NS@MIL-100(Fe) absorbs 5 wt.% of H₂ in 10 min. Surprisingly, 6.62 wt.% reversible capacity is maintained after 50 cycles. The modification mechanism is confirmed that the presence of oxygen vacancies and the synergistic effect of multivalent titanium in TiO₂ NS@MIL-100(Fe) greatly enhance the kinetic and thermodynamic properties of MgH₂.