The PVA sponge is special FOAM after acetalization, foam molding and grafting polymerization: i-PVA sponge. It is a non-fiber 3-dimensional porous structure in which PVA macromolecules combined with acid sodium polystyrene side chains. It has stable chemical structure, good biocompatibility and good hydrophilic, fluid absorption and blood-sucking performance. The product is a new surgical dressing and an excellent alternative of cotton gauze. It has been in clinical use for 20 years with mature technology and various usages.