The present invention relates to a health food composition and a pharmaceutical composition which contain refined polysaccharide derived from Styela plicata as an active ingredient to prevent or alleviate a bone-related disease, wherein the refined polysaccharide is isolated by adding water and protease to Styela plicata powder, making an extract, and performing ion exchange chromatography. The health food composition and the pharmaceutical composition have enhanced alkaline phosphatase activity and bone calcification ability.본 발명은 오만둥이(Styelaplicata) 분말에 물 및 단백질 가수분해효소를 첨가한 후 추출하고 이온교환 크로마토그래피를 이용하여 분리한 오만둥이 다당류 정제물을 유효성분으로 함유하는 골 관련 질환의 예방 또는 개선용 건강기능식품 조성물 및 약학 조성물에 관한 것이다.
