ZrO2 powder is prepared by low-temperature vapor-phase hydrolysis of ZrCl4. TG-DTA, XRD, Raman, BET, and TEM methods are used to investigate the particle size, phase composition, and agglomeration before and after heat treatment. The results show that the as-prepared ZrO2 powder is characterized by large surface area (150 m(2)/g), fine grain size (5.8 nm), and weak agglomeration. Additionally, the as-prepared ZrO2 powder shows predominantly tetragonal phase attributed to a grain size effect, This route is free of powder drying and calcination processes that are essential for wet chemical preparation, contributing to less agglomeration.