Abstract: The liquid (ethanol) wetting characteristic and dynamical mechanical property of polystyrene foams prepared by inverse emulsion with various densities have been studied. The wetting rate increases while the foam density decreases. The foams' cell sizes obtained from the relationship between the liquid wetting height and time correspond with the measured ones by SEM. The compressive modulus of the foam increases as temperature decreases and its density increases. The scaling exponent between the compressive modulus and density of PS foam is 2.02.