Cross-sea engineering plays a crucial role in the advancement of human society. However, due to geological constraints, cross-sea tunnels, as the primary infrastructure of such projects, are prone to instability and compromised safety during severe seismic events. Existing tunnel isolation materials face challenges such as susceptibility to cracking and difficulty in withstanding cyclic loads. Therefore, the development of tunnel isolation materials with strong elasticity and toughness is of significant importance. This study addresses this need by developing a high-elasticity, super-tough polymer-inorganic composite tunnel isolation material. Drawing on the microphase separation structure of polyurethane elastomers and polymer-based composite material interfaces, the innovative material was synthesized and characterized. Uniaxial and cyclic loading tests were conducted to evaluate its mechanical behavior, while scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to examine filler-polyurethane matrix bonding, microstructural changes, and interface modifications. These analyses revealed the synergistic mechanisms of the composite components. Results demonstrated significant enhancements in compressive performance and unit volume energy consumption, with the elastic modulus controllable at approximately 10 MPa, and the strain recovery rate stabilizing at 82 %. Moreover, a mix design model was developed for predicting compressive strength, elastic modulus, tensile strength, and elongation at break concerning PVA fiber content.