Abstract: ZrO₂(Y₂O₃) ultrafine ceramic powders were prepared by step-by-step precipitation and using several surfactants to modify their surface. The density, pore distribution, sinterability, particle morphology and phase composition of prepared powders were measured by mercury intrusion method,TEM,SEM and XRD respectively. It was shown that appropriate amount of surfaetant was favourable for controlling agglomeration and improving dispersity and fluidity of the powders. Small pore size and narrow pore size distribution of modified powders compacts were also obtained. In addition, the modified powders have spheric shape, fine and homogenous particle size,high content of t-ZrO₂ and good sinterability.