Oyster shell is produce by shucking process in oyster farming in southern coast of Korea. In average, about 6.7kg of oyster shell is produced as an industrial waste for 1kg of oyster flesh, and even only in last year, it is estimated that about 150,000ton of oyster shell is produced. Oyster shell is light weighted and the strength characteristic of it is similar to send. We produced mortar test piece using grounded oyster shell powder according to Filler and Fiber. So I wanted to measure the strength and use it as a baseline for follow-up studies.