The present invention relates to a multipurpose marine artificial structure protecting a coast from a seawater flow, preventing coastal erosion, and having a fishing bank function and, more specifically, to a multipurpose marine artificial structure functioning as a submerged breakwater and a wave dissipating block by damping a seawater flow from an outer sea by being horizontally installed along a coast, protecting a coast, preventing coastal erosion, and having a fishing bank function. The multipurpose marine artificial structure according to the present invention is capable of improving a submerged breakwater function effectively lowering seawater flow energy by being installed in a dock, harbor, and a coast, thereby obtaining an effect of protecting coast despite high wave poser. In addition, the multipurpose marine artificial structure according to the present invention is capable of not only protecting accidents due to a strong seawater flow by lowering the seawater flow energy and but also functioning as a fishing bank where fish, seaweed and the like can stably inhabit. Seawater between the sea and coast is smoothly circulated so that the present invention is capable of minimizing a sand loss that sand washed to the sea from the coast by a return flow. An existing submerged breakwater function capable of reducing a seawater flow from an outer sea is applied so that the present invention is capable of improving a water quality and protecting costal ecosystem by smoothly circulating seawater and preventing costal erosion. In addition, the multipurpose marine artificial structure is capable of being used as a seawall for anchoring a vessel in a fishing village. In case of this, the present invention is capable of minimizing casualties by absorbing heaving waves and being utilized as a marine facility for anchoring a vessel, as excessive reflected waves exist. The multipurpose marine artificial structure is capable of being easily and conveniently installed and
