The present invention relates to a method for purifying seaweed, which comprises a washing step (S100) of washing a foreign matter adhered to seaweeds with a washing solution, a step of dehydrating, deodorizing, decolorizing the washed seaweeds by dipping them in a dehydrating, deodorizing, (S200), a washing step (S300) of washing the dehydrated, deodorized, and decolorized seaweeds with a washing process composition, and a step of moistening, preserving and soaking the washed seaweeds in a preserving and coloring composition for 2 days, And a preservation treatment composition (400) for preserving and treating the seaweed, which is characterized in that it contains a preservative, a coloring process and a drying process (400) for preserving and drying the seaweed. It can be used as a material for living design and art work.본 발명은 생해조류에 부착된 이물질을 세척용액으로 세척하는 세척공정(S100), 상기 세척된 생해조류를 탈수, 탈취, 탈색 조성물에 2∼10일 동안 침지시켜 탈수, 탈취, 탈색시키기 위한 탈수, 탈취, 탈색공정(S200), 상기 탈수, 탈취, 탈색된 해조류를 세정공정조성물로 씻어내는 세정공정(S300) 및 상기 세정처리된 해조류를 보존, 착색공정 조성물에 2일 동안 침지시켜 보습, 방부, 착색처리하고 건조시키는 보존, 착색공정(400)；을 포함하는 것을 특징으로 하는 해조류의 보존처리방법과 이를 위한 보존처리조성물 및 보존처리된 해조류를 제공함으로써 아름답고 신비로움을 불러일으키는 해조류를 압화를 비롯한 각종 생활디자인 및 예술작품의 재료로 사용할 수 있다.
