In order to meet the demand of the impact protection and the buoyancy reserve of sea structure platform, a new energy absorption structure of filament wound composite constrained spherical buoyancy core material element was designed. The numerical simulation analysis and experimental test verification were carried out for the structure element by using the ABAQUS finite element software and electronic universal material testing machine in order to investigate the damage modes and energy dissipation mechanism. Further analysis of the mechanical response characteristics and damage modes shows that the key to the structural energy absorption design lies in the matching of the Poisson's ratio of the surface layer and the core material. The core material absorbs energy mainly through plastic compression damage and shear fracture damage, while the surface energy absorption is mainly through circular petal-shaped tensile fracture damage. The results show that this type of structural unit has excellent compression and energy absorption characteristics, and can realize the protection energy absorption and buoyancy reserve requirements of the offshore engineering structure platform.