For the high rockfill dam built on the foundation of large overburden depth, the traditional cushion materials cannot maintain the stability of geomembrane surface barrier and satisfy the requirement of adaptability to dam deformation. Laboratory experiments such as: permeability test, compressive strength test, flexural property test, interface direct test, and structural model test were carried to evaluate the permeability, basic mechanical property, interface strength, and adaptability to deformation of new porous cushion material (polymer permeable concrete). Additionally, comparative tests and analysis of traditional cushion material-non-fine concrete-were also conducted. The test results show that polymer permeable concrete not only has high mechanical strength and water permeability, but also has lower elasticity modulus and obvious toughness. It is indicated that polymer permeable concrete has stronger adaptability to flexural deformation compared to non-fine concrete. It is concluded that the polymer permeable concrete is a better alternative to the traditional cushion material of geomembrane surface barrier for high rockfill dam built on thick foundation.