The chemical reaction and phase evolution of perovskite lead zirconate (PbZrO3; PZ) nanoparticles, synthesized by the sono-assisted co-precipitation method, have been investigated. The nanopowders were characterized using the X-ray diffraction technique (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, transmission electron microscope (TEM) and differential scanning calorimetry (DSC). The perovskite phase, PbZrO3, begins to form at 600 degrees C and was completed at 900 degrees C. During the reaction of PbZrO3, only the tetragonal zirconia (t-ZrO2) phase was formed as an intermediate phase with low temperature range. Only Raman spectroscopy can identify the intermediate tetragonal zirconia (t-ZrO2) phase in PbZrO3 powders during calcinations process. The change in amount of the t-ZrO2 phase in PbZrO3 powders was estimated from Raman spectra as a function of the calcination temperature. Observations by transmission electron microscopy revealed that the PbZrO3 powders have a uniform spherical shape with nanosized particles. The average size of the particles is about 10.60 +/- 2 nm with narrow size distribution.