Static compression test of expanded polyvinyl alcohol with different densities and SEM observation of foam structures of different compressive stage were carried out. Mechanical property and cushion mechanism of expanded polyvinyl alcohol were studied. The results showed that compressive stress-strain curve of material includes three stages, which are linear elasticity, plastic yield and densification; the difference of mechanical property in different compressive direction indicates structural anisotropy of the material; elasticity modulus and yield strength of the material are affected by foam structure, which increase with increasing density; energy absorption efficiency of material can be maximizing when strain is about 0. 55; the final compressive deformation mechanism is mainly bending deformation of pore wall; the influence of gas on compressive mechanical property can be ignored when pore size of material is very big. The purpose was to provide references cushion packaging design using expanded polyvinyl alcohol of different foam structure.