Abstract: Extruded polystyrene foaming plate was prepared using carbon dioxide (CO2)and ethanol (EtOH) as physical blowing agents. The effect of CO2/EtOH ratio on expansions and cellular morphology of the foam plate were discussed. The foam density and foam morphology of extruded polystyrene foaming plate were tested by densitometer and scanning electron microscopy. The density of extruded polystyrene foaming plate decreased with increasing content of blowing agents. Specially, the cell density increased and cell size decreased with increasing CO2 content and the cell size increased with increasing EtOH content.