Abstract: Single phase multiferroic BiFeO₃ powder was prepared by improved solid state synthesis,and dense BiFeO₃ ceramics were fabricated by spark plasma sintering(SPS) process.The particle size of BiFeO₃ powder used for second sintering by SPS ranging from 0.1μm to 10μm.It is found that the sample has not only single phase but also high density of 97.3% when sintered at 650℃.The piezoelectric coefficient d33 of the sample is 13.6 pC/Nat room temperature.Oxygen and vacuum annealing conditions impact dielectric behavior of BiFeO₃ ceramics prepared by SPS technique obviously.Two kinds of dielectric relaxation following the Arrhenius law were detected in low and high temperature ranges,respectively.The low temperature dielectric relaxation could be almost completely removed by annealing in vacuum and it should be assigned to be a valence fluctuation of Feions,while the high temperature dielectric relaxation was proposed to stem from the short range motion of oxygen vacancies.