Ternary oxides containing Sn2+ are rare and difficult to prepare using solid state reaction due to disproportionation of Sn2+ at high temperature. In this paper, nanoparticles of barium titanate doped with different amounts of Sn2+ consisting of single phase perovskite structure were successfully synthesized for the first time by using a microwave-assisted solvothermal reaction. The particle sizes were about 20-40 nm in diameter and increased with increasing the amount of doped tin. Solidified ceramic bodies were obtained using a spark plasma sintering method under argon atmosphere avoiding the disproportionation and oxidation of Sn2+ in the air. The grain size and dielectric constant of the sintered body decreased with increasing the amount of doped tin.