Nanosized Ce_0.95M_0.05O₂(M=Fe³⁺, Nd³⁺, Eu³⁺) solid solutions were synthesized via hydrothermal method. The micro-crystalline structure and spectra characteristics were investigated systemically. X-ray diffraction (XRD) results showed that doped samples exhibited single phase fluorite cubic structure, while no impurity phases corresponding to the doped ions oxides were observed. This result indicated that the doped ions had been doped into the lattice of CeO₂ and formed solid solutions. The crystalline sizes of the samples were calculated lower than 20 nm. The electron transition properties of the solid solutions were characterized by UV-Vis spectra. Red-shift of absorption edges of the doped solid solutions was observed. Meanwhile, the band gap energies were fitted and it was found that the obtained values from large to small is CeO₂ (3.13 eV)>Ce_0.95Eu_0.05O₂ (3.04 eV)>Ce_0.95Nd_0.05O₂ (2.94 eV)>Ce_0.95Fe_0.05O₂ (2.75 eV). The photoluminescence (PL) spectra displayed that the intensities of the doped sample emission peaks were lower than that of pure CeO₂. Among them, the peak of the solid solution with Fe³⁺ ions possessed the lowest intensity. It can be explained that the doping of Fe³⁺ ions would introduce more defects in the lattice, which would hinder the recombination of electrons and holes. The solid solutions were added into Mg₂Ni-Ni as catalysts and the Mg₂Ni-Ni-5%Ce_0.95M_0.05O₂ composites were obtained via ball milling method. The electrochemical and dynamic hydrogen storage performances were tested systematically. It was showed that the Ce_0.95M_0.05O₂ solid solutions could improve the electrochemical discharge properties, the maximum discharge capacities were Ce_0.95Fe_0.05O₂ (874.8 mA h·g^-1) >Ce_0.95Nd_0.05O₂ (827.8 mAh·g^-1) >Ce_0.95Eu_0.05O₂ (822.7 mA h·g^-1) >CeO₂ (764.9 mAh·g^-1), respectively. Meanwhile, the catalysts also could enhance the electrochemical cycle stabilities of the composites effectively. The capacity retention ratio after 20 cycles were Ce_0.95Fe_0.05O₂ (49.8%)>Ce_0.95Eu_0.05O₂ (49.7%)>Ce_0.95Nd_0.05O₂ (46.3%)>CeO₂ (34.1%). The high rate discharge (HRD) properties of the composites were characterized, and it was proved that the solid solutions catalysts could improve the large current discharge performances of the composites. For instance, when the discharge current density was 200 mAh·g^-1, the HRD were Ce_0.95Fe_0.05O₂ (59.5%)>Ce_0.95Eu_0.05O₂ (57.4%)> Ce_0.95Nd_0.05O₂ (55.7%)>CeO₂ (54.4%). The influence of the catalysts on the H diffusion capacity in the composites was evaluated by constant potential step technique, and the H diffusion coefficient was: Ce_0.95Fe_0.05O₂>Ce_0.95Eu_0.05O₂>Ce_0.95Nd_0.05O₂>CeO₂. The catalysis effects of the solid solutions were closely related to the concentration of oxygen vacancies, lattice defects in the lattice and the characteristic of easy to change valences of the doped ions.