Regenerated cellulose/polyvinyl alcohol (PVA) blend membranes were prepared from a solution of cellulose and PVA in an ionic liquid of 1-allyl-3-methyimidazolium chloride (AMImCl). SEM images showed that the phase separation on the mixture was severely formed when the content of PVA was higher than 10% by volume. However, when the content of PVA in the mixture was lower than 6%, the cellulose and PVA were well-distributed. The regenerated blend membranes using the AMImCl presenting reasonable crystallinity were superior to those of regenerated pure cellulose membrane. In conclusion, the compatible properties of blend membranes from regenerated cellulose/PVA (6%) were improved and the blend membranes kept original biodegradability.