Oyster is the seashell which is large in quantity and very common to be eaten in Penghu. However, the waste shells often cause environment pollution and trash problems. Recycling and utilization of waste shells would achieve the purpose of reducing waste and reusing of green energy. National and international researches indicate that shell powder has bacteriostatic function. In this study, two kinds of oyster shell powder, unheated and heated for one hour at 300℃, were used to replace 50% and 100% of black fine sand separately in Babylonia areolata aquaculture to evaluate the efficiency of water purification. The result showed that the growth of Babylonia areolata cultured in the 100% oyster shell powder substrate, unheated or heated, were both the best; then followed by the substrate mixed by 50% oyster shell powder and 50% black fine sand. The coral sand substrate and black fine sand substrate were both the worst. The result of total plate count, coliform bacteria, and vibrio clades in water samples showed that the bacterial count of coral sand substrate was relatively higher while heated oyster shell substrate was lower. The result of water quality detection showed that there was no significant difference between each group. Most Babylonia areolata aquaculture in Taiwan use black fine sand as substrate; however, it is detrimental to the growth of Babylonia areolata because that it often causes water to be turbid and contains lots of bacteria. If it is able to use waste oyster shell power to replace black fine sand and coral sand in Babylonia areolata aquaculture, the cultivation rate and growth rate would be enhanced and the disease would be reduced.