The ambient-temperature stable nanosized ZrO₂ particles with different crystallographic structures were prepared by codeposition method. Their crystallographic structures, grain size, specific surface area and size distribution were characterized by powder X-ray diffraction (XRD), laser raman spectroscopy, N₂ physical adsorption, transmission electron microscopy (TEM) and dynamic light scattering (DLS) respectively. Therewith the effect of preparation temperature and modifier doping on the crystallographic structures of particles was investigated. The results show that the nanosized ZrO₂ powders without Y₂O₃ doping calcined at 850℃ are monoclinic ZrO₂ with an average grain size 51.3 nm and a specific surface area 35.17 m²/g; the powders doped with 4.5% Y₂O₃ (molar fraction) and calcined at 600℃ are tetragonal ZrO₂ with a specific surface area 39.01 m²/g and an average grain size 19.2 nm; the powders doped with 8.5% Y₂O₃ (molar fraction) and calcined at 600℃ are cubic ZrO₂ with a specific surface area 46.53 m²/g and an average grain size 12.7 nm.