Hydride hydrolysis reaction is a promising method for on-site hydrogen production with high capacity. However, ensuring a certain amount of water and the formation of a passivation layer in the produced material is crucial to interrupt the reaction. In this experimental study, multiple hydrolysis experiments using chloride solutions at concentrations of 0.1 M, 0.5 M, and 1 M were investigated. Hydrolysis kinetics curves were measured at different temperatures. The resulting hydrolyzed products underwent analysis of phase and morphology using XRD and SEM scanning techniques, and the hydrolysis mechanism was examined. The results demonstrated that the hydrolysis activation energy for the 0.1 M, 0.5 M, and 1 M MgCl2 solutions was determined to be 42.62 ± 7, 37.4 ± 0.6, and 27.1 ± 0.5 kJ/mol, respectively, establishing the impact of concentration on the hydrolysis kinetics. Moreover, water reduction tests conducted under the original conditions revealed that using 0.1 M FeCl3 and 0.1 M AlCl3 solutions with 5 mL water yielded a hydrolysis yield of 1500 mL/g, and the conversion rate can reach 97 % in 2 mL of water in 0.5 M FeCl3 solution. These remarkable hydrolysis properties of MgH2 are significant for the study of related magnesium-based alloy hydrides.