Abstract: To enhance hydrogen absorption/desorption kinetics while reducing Mg-H bond stability without compromising storage capacity, rare earth elements of La and Y, transition metal Ni, and In were incorporated into the Mg-based alloy. The In-containing alloy was subjected to melt spinning to produce an amorphous-nanocrystalline structure. Crystallization annealing at 400 ℃ for 4 h was performed to enhance the hydrogen storage properties. The phase transformations and structural evolution of Mg₉₀La₂Y₂Ni₆ and Mg₉₀La₂Y₂Ni_4.8In_1.2 alloys were systematically characterized before and after hydrogenation. The results revealed that melt spinning yielded a predominantly amorphous structure with nanocrystalline domains in the Mg₉₀La₂Y₂Ni_4.8In_1.2 alloy. The as-cast Mg₉₀La₂Y₂Ni₆and Mg₉₀La₂Y₂Ni_4.8In_1.2, annealed Mg₉₀La₂Y₂Ni_4.8In_1.2alloys consisted of Mg, Mg₂Ni, La₂Mg₁₇, and YNi₃ phases. In doping resulted in the formation of MgIn and Mg₂NiIn solid solutions within the Mg and Mg₂Ni matrices, respectively. Notably, In incorporation induced lattice contraction in Mg while expanding the Mg₂Ni lattice parameters. Crystallization annealing facilitated complete crystallization, achieving homogeneous element distribution and microstructure refinement. The newly generated grains and grain boundaries established additional pathways for hydrogen diffusion. Kinetic measurements demonstrated that the annealed Mg₉₀La₂Y₂Ni_4.8In_1.2 alloy exhibited optimal hydrogen storage capacity at 260-320 ℃, and can completely dehydrogenation within 500 s at 320 ℃ and within 1 500 s at 260 ℃, with a significantly reduced activation energy of 63.36 kJ/mol.