The (Pb1-x, Cax)TiO3, (x=0.12 to 0.5) ceramics were sintered, and the relationship between dielectric, piezoelectric properties and microstructure were classified as a function of Ca content. There existed no phase boundaries over the range of Ca content of 0.12 to 0.5 mol. However, the ratio of kt and kp was drastically changed as a function of Ca content. These changes were related with the appearance of 90° domains and superlattice.