Barium titanate (BaTiO3) thin films were prepared on MgO (100) substrates using metal naphthenate solution by a coating-pyrolysis process. Amorphous films pyrolyzed at 470℃ were crystallized to BaTiO3 phase by heat treatment at higher temperatures. The crystallinity and alignment of the films depended on temperature and on atmosphere during heat treatment. Epitaxial BaTiO3 film having (100)-orientation was obtained by heat treatment at 900℃ under oxygen partial pressure of 2×10-4 atm. The epitaxial BaTiO3 film had a lattice constant of 0.4016 nm and displayed a smooth surface with some pores dispersed on the surface. By heat treatment in air, amorphous BaTiO3 film was obtained at 900℃ or below, and textured film with less strong (100) orientation was obtained at 1,200℃ and consisted of grains with diameter about 0.3 μm.