The bulk Mg-M (M = Nickel [Ni], cerium [Ce], and Lanthanum [La]) alloys are successfully ameliorated by high-energy ball milling (HEBM) to modify the hydrolysis H(2)generation performance in simulated seawater solution (3.5 wt% NaCl). The H(2)generation kinetics, rate-limiting steps, thermodynamics and the hydrolysis mechanism are investigated by combining the fitting results of the hydrolysis curves and microstructures information. The results indicate that the as-cast Mg25Ni possesses higher generation capacity and faster initial rate. The capacities of as-cast Mg25Ni, Mg30Ce, and Mg30La alloys at 48 degrees C within 180 minutes are 760 mL g(-1), 725 mL g(-1), and 525 mL g(-1). The hydrolysis H(2)generation apparent activation energies of the as-cast Mg25Ni, Mg30Ce, and Mg30La alloys are 30.92, 17.05, and 28.04 kJ center dot mol(-1), respectively. The HEBM technique can elevate the hydrolysis performance of Mg-M alloys. And the highest H(2)producing capacity as high as 589 mL g(-1)is obtained by HEBM Mg30La alloy at 48 degrees C within 30 minutes. The hydrolysis apparent activation energiesE(a)are 9.57, 14.65, and 23.88 kJ/mol for HEBM Mg25Ni, Mg30Ce, and Mg30La alloys. The initial rate and the final yield of H(2)generation for Mg-based alloys are affected by the activity of matrix alloy, microstructure, particle size, surface state, and many other factors.