Preparation of LuFe2O4 ceramics under vacuum environment was investigated together with the structural, dielectric, and magnetic characterization. Single-phase LuFe2O4 could be obtained by the present process and the crystal structure was identified to be rhombohedral in space group inline image. An obvious dielectric relaxation with activation energy of 0.29 eV was observed between 175 and 275 K. The Néel temperature of the present ceramics was ~250 K, and a reentrant spin glass transition was indicated at ~216 K. Two anomalies were observed in the DSC curve, which were relative with the ferrimagnetic transition and 2D–3D charge ordering transition of LuFe2O4. Meanwhile, a remarkable decrease appeared in the dielectric constant of the as-magnetized LuFe2O4 sample, implying the magnetodielectric effect in the present ceramics.