TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Parameters: Reduction potential difference between the dissimilar metals takes hydrogen as the standard potential, the mutual potential difference between the metal adopted by cathode and the metal adopted by anode is less than or equal to 3.49 V, and both metals can be used as cathode material. Mutual potential difference between the metal adopted by cathode and the metal adopted by anode is 0.71-3.49 V. Mutual potential difference between the metal adopted by cathode and the metal adopted by anode is less than or equal to 2.01 V, and both the metals can be used as cathode material. Preferred Components: Reduction potential difference between the dissimilar metals takes calomel electrode (mercurous chloride (Hg2Cl)2) as the standard potential. Metal of anode adopts the waste product having magnesium alloy or aluminum alloy. Metal of cathode adopts stainless steel or platinum. Electrolyte solution in the electrochemical reaction adopts sodium chloride water, physiological salt solution or potassium chloride (KCl) aqueous solution whose potassium ion and chloride ion will not change hydrogen ion and hydroxide ion in the water when being dissolved in the water. Preferred Process: Combining step of the two metals as the cathode and anode involves: pressing and shaping through the mode of crushing after one metal is crushed, pressing and roll milling, and the other metal with a proper structure in the mode of net, gill net or powder is rolled on this shaped metal; and after the anode metal is melted into liquid, dipping and combining the single face of the cathode metal to shorten the electron transmission path between the cathode and anode in the electrochemical reaction and to improve the effect of hydrogen generation. Mode of crushing, pressing and roll milling involves: pressing and shaping through the mode of crushing after the anode metal is crushed, pressing and roll milling, and the cathode metal with a proper structure in the mode of net, gill net or powder is rolled on the shaped anode metal. Cathode metal can be bent for multiple times to increase its reaction faces before being dipped. Dipping mode is carried out by adopting the mode of middle dipping to make the cathode metal expose out of the two ends of the anode metal.