Ion exchange technology was applied to this study to treat nickel ion from plating wastewater which contains heavy metal, bringing environmental problems such as chromium, zinc, copper, and lead. To separate nickel ion from wastewater, the nickel recovery unit (NRU) used a column packed with strongly acidic cation resin. The leak of the ion appeared when rinse water that has a concentration of 1.8 g-Ni/L-distilled water flowed into the NRU as much as 20 times the bed volume. At this time, the capacity of resin packed in the column was 1.7 meq/ml and over 99% nickel ion was removed. Sulfuric acid was employed with a reagent in order to regenerate nickel ion from the resin adsorbed. Nickel ion recovered by sulfuric acid was obtainable up to 120 g-Ni/L. The concentration of sulfuric acid was 2N and space velocity was 2/h. Acid retardation unit (ARU) experiment could be accomplished by deacidification to control the pH of the solution to recycle in the plating process. The composition was 30 g-Ni/L and the pH maintained was over 3.0.