Water electrolysis is one of the most common ways to produce hydrogen gas. It has several merits, such as: high efficiency, high purity, and easy use. In this paper, electrodes with different magnetism are adapted on the hydrogen production by water electrolysis, and the influences of magneto-hydrodynamics on the electrolysis process are discussed. The influences of working parameters related to magnetism and water electrolysis are also discussed as well. According to the experimental observations, the direction of magnetism will determine the direction of Lorentz force, the convection of electrolytic solution, the direction of the bubbles motion, and then affect the efficiency of water electrolysis. Furthermore, ferromagnetism electrodes are more affected by magnetism, and multiply the Lorentz effect. It reduces the polarization and over-potential during electrolysis, and thus increases the effectiveness of hydrogen production. With the magnetic field at room temperature, electrode spacing of 2 mm and a voltage of 4 V, nickel electrodes (ferromagnetism material) can promote current density by 14.6%, and platinum electrodes (paramagnetism material) can promote current density by 10%. The promotion of current density is not significant for graphite electrodes (diamagnetism material). It indicates that the magnetic force does enhance the efficiency of water electrolysis, and ferromagnetism is the best choice for electrodes. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.