Water debinding is a new technique for ceramic injection molding. Compared with conventional thermal debinding, water-debinding has many advantages, such as environment friendly, high debinding rate, and suitable for molding large sized ceramic part. In this paper, binder system, based on polyethylene glycol(PEG) and polyvinyl butyryl(PVB), was mixed with 3Y-TZP(ZrO2) powder, and feedstock with 54vol% of ceramic powders was obtained. Shear viscosity of the feedstock was 300Pa·s at 190oC, when shear rate was 100/s, similar to the feedstock based on paraffin wax(PW). SEM showed that the feedstock and sintered parts were both homogeneous. Water debinding dynamics was also studied. For the 5mm x 6mm x 42mm sample, 65% of PEG could be extracted within 2 hours in water at 40oC, and the bending strength of sintered compacts was above 900MPa. The samples with thickness from 9mm to 12mm were made and the green parts could be debinded in water without any defects. The results showed water debinding method could increase the debinding rate and was effective to fabricate large sized ceramic parts.