Crystalline BaTiO 3 nanoparticles were synthesized by hydrothermal process. The influences of PVA concentration on the phase formation, the size, the shape and dispersibility of BaTiO 3 nanoparticles were determined by XRD, FE-SEM, TEM and the thermal analysis. After PVA solution added into the barium precursor, high purity cubic perovskite BaTiO 3 nanoparticles were successfully obtained with well dispersion. The size and the shape of BaTiO 3 particles were also be controlled by the concentration of PVA with lattice parameters almost unchanged. In addition, spherical BaTiO 3 grains with average size of 68.8 nm were obtained when 0.02 g L −1 PVA was added into the barium precursor, which process the best morphology and highest dispersibility.