The effect of calcining temperature on microstructures and electrical properties of modified lead zirconate titanate ceramics has been investigated. Specimens of the modified lead zirconate titanate ceramics, formed with different powders calcined over the temperature range from 800 to 950 °C, were prepared by roll forming process. It is observed that the calcining temperature of the powders alters the grain size, which, in turn, modifies the electrical properties of the ceramics. The results also show that dielectric constant, saturated polarization and piezoelectric coefficient tend to increase with increasing calcining temperature up to 900 °C and then to sharply decrease. The best electrical properties were obtained from the samples with the calcining temperature of 900 °C. At the lower calcining temperatures, a small PbO excess seems to result in PbO-rich grain boundaries and anomalous grain growth during sintering process. In addition, when the calcining temperature was increased to 950 °C, a PbO deficiency appears to take place by breaking up the stoichiometry.