Calcined Ni–Al complex hydroxide (NA12) was produced through calcination at 400°C, and its capability on phosphate ion adsorption was examined. Initially, the physicochemical characteristics including specific surface area, the number of hydroxyl groups, pore volume, scanning electron microscope images, and X-ray diffraction patterns of calcined Ni–Al complex hydroxides were evaluated. The level of phosphate ion adsorbed onto NA12 in the value of 128.5 mg/g was higher than that of other compared adsorbents. This study indicated that the level of phosphate ion adsorbed using calcined Ni–Al complex hydroxide was correlated to the properties of an adsorbent surface. Moreover, the binding energy of the NA12 surface before and after the phosphate ion adsorption was also determined, and phosphorus energy (2p and 2s) could be detected after adsorption. The results demonstrated that the NA12 surface properties were important for phosphate ion removal from the aqueous solution. Additionally, the effects of pH, temperature, and contact time on the phosphate ion adsorption were also investigated. The results confirmed a potent recovery of the phosphate ion (over 90%) when using a NaOH solution at 1000 mmol/L in this experiment. Thus, NA12 is a promising adsorbent for the phosphate ion.