Oysters are the most widely produced shellfish culture in Korea and 90% of their weight. Main component of oyster shell is CaCO3 and an appropriate calcination temperature was derived using thermo-gravimetric analysis. The difference in components for each calcination temperature was confirmed and the adsorbent was manufactured by activation. The oyster shell adsorbent surface area was 5.72m2/g with pores in the mesopore range. The adsorption amount was 37.44 mg/g. Therefore, the possibility of using oyster shell as an adsorbent was confirmed.