A fluid-structure coupling and dynamic model of ship anti-shock layer for underwater explosion wave isolation is developed to describe the complex structural dynamics and hydrodynamics characteristics of the anti-shock layer due to underwater explosion based on the multi-DOF dynamic theory, Taylor's flat plate model and DAA1 methods. The anti-shock layer shock response is split into three sequential steps: stage I is the one-dimensional fluid-structure interaction problem during the blast loading event, and results in a accelerated motion of the outer face sheet, and the cavitation occur in the water; during stage II the core crushes while the velocity of the outer face sheet bring down, additional impulse due to the water particles play an important role; stage III is the retardation phase over which the anti-shock layer is brought to rest by elastic restoring force and fluid pressure. The third-stage analytical procedure is used to obtain the dynamic response of the anti-shock layer to an underwater explosion. The analytical procedure and case study indicate the proposed model can deal with the ship anti-shock layer with complex core structures and the core density have a significant impact on the cushion effects of the ship anti-shock layer. The influence of the core density to the cushion performances is analyzed. These performances can be used to determine the optimal geometry to maximize shock resistance for a given mass of the anti-shock layer.