Recently prestressed concrete is actively and widely used for marine structure. The prestressed concrete pile (PC pile), which is one of the most populor precast prestressed concressed concrete, can be used for the basic structral member.
　In case of marine structres, strength and deformation characteristics of PC piles subjected to repeated loading must be considered. The present paper deals with the results of repated bending tests (some are reversible repeated tests) as well as static beding tests. And considering the resuts, the auther suggests two design methods of the PC pileused for marinctures.