(1−x)K0.5Na0.5NbO3-xSrMnO3 (0.02 ≤ x ≤ 0.08) (KNN-xSM) ceramics were fabricated by a conventional solid-state technique. X-ray diffraction of the samples revealed that the crystal structure changes from orthorhombic to tetragonal, and finally to pseudocubic symmetry with increasing x. Temperature dependence of dielectric properties showed that the temperature (T m) corresponding to the maximum of dielectric permittivity decreased with increasing x. Two dielectric relaxation processes occurred at high temperatures, which were attributed to grain and grain boundary responses, respectively. Polarization hysteresis loops (P-E) at different electrical fields were displayed. P rmax degenerated with the increase of SM due to the thermally activated leakage current increases. The relationship between electrical properties and defect compensation mechanism is discussed.