Pure phase perovskite relaxor-based (1 – x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–PT, x = 0.2–0.4) ferroelectric ceramics were prepared by the reaction-sintering method sintered at 1240–1250 °C. The synthesized ceramics exhibit rather homogeneous microstructure morphology and relatively high density. The content of PbTiO3 (PT) exerts successive influences on sintering capability, phase structure and electrical properties of the PMN-PT ceramics. With the increase of the PT content, the crystal structure of the PMN–PT ceramics changes gradually from the rhombohedral phase, across the coexistence of rhombohedral phase and tetragonal phase, and to the tetragonal phase, accompanied by the change of the dielectric response character from typical relaxor ferroelectrics to normal ferroelectrics. The morphotropic phase boundary (MPB) of the PMN–PT system is determined locating at x = 0.3–0.34 based on the structure analysis and the electrical properties measurements, in which the PMN–PT ceramics with the MPB composition exhibit enhanced microstructure and excellent electrical properties, especially superior piezoelectric properties.