In this work, the dielectric properties of La 0.8 Bi 0.2 Fe 0.7 Mn 0.3 O 3 ceramics have been investigated in a temperature range of 76–320K and a frequency range of 300 Hz–10MHz. Two thermally activated dielectric relaxations were observed with the activation energy around 0.283±0.007eV for the low-temperature relaxation and 0.268±0.007eV for the high-temperature relaxation. Annealing in N 2 and O 2 can destroy and create the high-temperature relaxation, respectively. But the treatments have no significant influence on the low-temperature relaxation. The low-temperature relaxation was found to be bulk effect related to the dipolar effect due to the hopping polarons, and the high-temperature relaxation was associated with the Maxwell–Wagner relaxation due to surface-layer effect caused by hopping polarons blocked and trapped at the surfaces of the sample.