Single phase Pb(Fe₁2/Ta₁2.)O₃, ceramics were successfully synthesized from the powders prepared by solid state reaction (sintering temperature: 1100℃, density: 9.3 g/㎠, average grain size: 5.1± 1.2mm, space group: Pm3m). Their dielectric properties measured at -150∼50℃ showed the maximum relative dielectric constant of 31000 at -41℃. 1 kHz, and typical relaxor ferroelectrics characteristics such as diffuse phase transition and dielectric relaxation phenomena. However, the diffuseness of phase transition decreased and the dielectric properties became more normal ferroelectrics as the time of annealing at 1000℃ increased. By using Raman spectroscopy, it was revealed that the Fe³⁺ and Ta⁵⁺ ions in the as-sintered Pb(Fe₁2/Ta₁2.)O₃, are stoichiometrically 1 : 1 ordered within the short-range that can not be probed even by transmission electron microscopy, and this stoichiometric 1 : 1 ordering is enhanced by the annealing. The relaxor ferroelectric characteristics in the as-sintered Pb(Fe₁2/Ta₁2.)O₃, could be correlated with the stoichiometric 1 : 1 short-range ordering of B-site cations, and the decrease of relaxor ferroelectric characteristics in the annealed Pb(Fe₁2/Ta₁2.)O₃ could be correlated with the enhanced stoichiometric 1 : 1 short-range ordering of B-site cations