It is widely accepted that colloidal stability has a great effect on the quality of the products in wet processing of ceramics such as electrophoretic deposition. In this work, colloidal stability of submicron PZT powders in ethanol was studied. Zeta potential and viscosity of PZT powder suspension as a function of pH were measured. Electrosteric effect resulted from the addition of PVA polymer to the suspension was also investigated. The dispersing quality of the polymeric solvent was quantified by viscosity measurement and represented by a solvent quality parameter. The effect of polymer addition to the PZT suspension on zeta potential was also determined as a function of pH. The electrostatic effect was also discussed using the DLVO theory. Lastly, electrophoretic deposition (EPD) was carried out using the identified optimum suspension conditions.