(Pb 0 . 8 8 - x Sr x Sm 0 . 0 8 )(Ti 0 . 9 8 Mn 0 . 0 2 )O 3 ceramics; x=0.05-0.25 were prepared by conventional mixed-oxide technique, with sintering temperature at 1125-1250 o C. Microstructural and compositional analyses of these doped ceramics have been carried out using X-ray diffraction (XRD) and scanning electron microscope (SEM). The effects of dopants and the sintering temperature on the piezoelectric and dielectric properties of Sm-modified PbTiO 3 ceramics have been investigated. We successfully showed that all Sr additive samples have maximum density and thickness electromechanical coupling coefficient, k t (>0.55) at 1200 o C sintering temperature, and still keep small planar electromechanical coupling coefficient, k p . In other words, the optimum sintering condition was found.