0.5 wt. % B2O3 doped BaZrxTi1-xO3 ceramics (x = 0, 0.1, 0.2, 0.3, 0.4) were synthesized by adapting the solid-state synthesis method. B2O3 used as a sintering additive in the BT and BZT ceramics can vaporize easily at high temperatures, so it can be adopted as a vapor dopant. The influence of the substitution content on the crystallographic structure, phase transition, grain size, microstructure and physical properties of BT and BZT ceramics were discussed. Materials Pro+ image analysis software was used for the measurement of grain size of piezoelectric ceramics. XRD analysis at room temperature revealed that a structural transformation from tetragonal to rhombohedral with increasing ZrO2 content in the BT matrix. The scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) were employed to investigate the microstructures and surface-fracture morphologies of the sintered samples. The relative densities and open porosity were measured by the Archimedes' immersion method in distilled water.