Expanded polystyrene (EPS) geofoam is a novel kind of geosynthetic material, which has some prominent features, e.g. light weight, compressibility well, water resistant and heat preservation. Therefore, EPS can be used as a lining structural layer of underwater slope of expansive soil canal to reduce expansive pressure acting on concrete lining face slab and maintain matric suction of expansive soil, thus make the slope of expansive soil canal more stable. In order to further explore the mechanical characteristics of EPS under compression in this application, a set of one-dimensional compression tests and compressive creep tests on EPS with three different densities (14.7kg/m3, 17.05kg/m3, 23.4kg/m3) were conducted, the experimental results show that the stress-strain relationship of EPS is significantly nonlinear and the creep strain is significant under long-term loading. Based on the experimental results, a mathematical model for describing the whole compression process of EPS is proposed.