Abstract: The effects of different firing temperatures on the stability of perovskite phase, grain size, and dielectric properties were investigated by XRD, TEM, SEM and dielectric measurements. The dielectric ceramics of Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃-BaTiO₃ system were obtained by chemical coprecipitation in water. The ceramics have higher dielectric constant (7003-9714), lower firing temperature(950-1150℃), quite uniform microstructure with grain size less than 2.5 mp, and lower temperature coefficients of capacitance. As a result, it was confirmed that the simple and low cost chemical route used namely coprecipitation in water is a desired method for preparing high property dielectric materials applicable to multilayer capacitors.