The cellulose acetate/poly(ethylene glycol) (CA/PEG) blend with a weight ratio of 50/50 was solution blended followed by supercritical carbon dioxide foaming and the PEG leaching process. Interestingly, a bimodal open-celled structure (BMOCS) with networks is obtained. Large cells are developed from the cell nuclei formed during rapid depressurization, while small cells are formed by leaching of PEG out from the blend foams. The open-celled structure with networks is developed by the synergistic effect of leaching of PEG and rupture of some cell wall. The influences of foaming temperature and pressure on cellular structure for CA and CA/PEG blend foams were studied. The foam densities of blend foams after leaching PEG (0.18-0.41 g/cm(3)) are higher than those of CA foams (0.13-0.20 g/cm(3)). The leaching contents of PEG out from CA/PEG blend foams are in the range of 89.0%-99.1%.