By electrolysis of saline solution, caustic soda is produced, the anode is made of chlorine, and the cathode is reacted to make hydrogen and caustic soda. According to the product separation method, the chlor-alkali industry forms two different production processes: ion membrane electrolysis (diaphragm electrolyzer) and mercury electrolysis The anode reactions of the two electrolysis methods are basically the same, but the cathodic reaction is different. The mercury electrolysis method uses mercury with high hydrogen evolution overpotential as the cathode material. Before reaching the hydrogen evolution electrode potential, NA+ in the solution has been discharged at the cathode and mercury is generated from the mercury. The amalgam and sodium amalgam flow into the mercury-removal tank to react with water to form caustic soda. However, the mercury method consumes a lot of electricity, and mercury has been lost causing environmental pollution. For the electrode, the working voltage of the graphite anode is 8A/DM2, and the coated anode can be doubled up to 17A/DM2. In this way, the product can be exponentially increased in the same electrolysis environment and the quality of the produced product is high, and the purity of chlorine is high. Therefore, the use of titanium coated electrode diaphragm electrolytic cell is the first choice of chlor-alkali industry.