Research has been carried out on the synergism of a mixture of andisol soil and foundry sand as Cu(II) ion adsorbent. This study aims to determine the effect of mixing andisol soil and foundry sand on the absorption of Cu (II) ions and to study the type of isotherm and its adsorption kinetics model. The adsorbent was activated with 3 M NaOH. The acidity of the adsorbent was analyzed using the specific total acidity test method. The final concentration of Cu (II) ions was analyzed using AAS (Atomic Absorption Spectroscopy). The optimum adsorption conditions were obtained based on variations in composition, pH, and contact time. The adsorbent was made with variations in the composition of andisol: foundry sand 100:0, 75:25, 50:50, 25:75 and 0:100 (w/w). The effect of adsorption conditions was carried out by varying the pH of the copper (Cu) solution from 3-7. The effect of contact time was varied at 15-135 minutes with 15 Minute intervals.