A hierarchical porous polymer (HPP) with high porosity (91.9%) was synthesized. The HPP shows pressure-dependent elastic deformation behavior for ssPCMs. The interaction in HPP induces the stability of the β phase of 1-octadecanol. The HPP reduce the extent of the supercooling of 1-octadecanol (37%) effectively. The ssPCMs have high adsorption of 1-octadecanol and high energy storage density.