The microstructural evolution of BaTiO3 ceramics during cubic-hexagonal phase transformation was investiga-ted. In the case of phase transformation from cubic to hexagonal BaTiO3 the hexagonal phase nucleated at the surface region of specimen. On the other hand in the case of that from hexgonal phase to cubic, cubic phase was initiated at the center region of specimen. And fast grain growth and irregular grain boundary shape could be also observed during these transformation processes. Besides low densified hexagonal BaTiO3 specimen was made with low forming pressure. The phase transformation of these specimens toward cubic phase was relatively retarded comparing with dense hexagonal BaTiO3 specimens. was made low forming pressure.. The phase transformation of these specimens toward cubic phase was relatively retarded comparing with dense hexagonal BaTiO3 specimens. These results were explained that hexagonal BaTiO3 had lowder surface energy than cubic phase,