Abstract: This invention relates to a piezoelectric ceramic material of a quarternary system, formulated on the basis of ternary system materials (PCM and PMN). Said quarternary system piezoelectric ceramic material consists of lead niobate with Mg (Pb (Mg.sub.1/3 Nb.sub.2/3)O.sub.3, lead niobate with Mn (Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3), lead zirconate (PbZrO3) and lead titanate (PbTiO3), and possesses excellent properties for large power output purposes, and is suitable for making piezoelectric transformers of large power output. A single piece piezoelectric transformer (dimensions 100.times.25.times.36 mm3) using the material of the present invention is found to have a maximum output power of 50 W. The material according to this invention has a simple preparing process, a wider and lower sintering temperature range, is fine and compact in ceramic structure, and has a high rate of success of finished products.