Epitaxial and preferentially oriented Bi4Ti3O12 thin films were grown using pulsed laser deposition on LaAlO3(001) and Al2O3(0001) substrates, respectively, with La0.5Sr0.5CoO3 bottom electrode layers. X-ray diffraction analysis shows that the Bi4Ti3O12 films are grown (001) and (104) oriented on La0.5Sr0.5CoO3(001)/LaAlO3(001) and La0.5Sr0.5CoO3(111)/Al2O 3(0001), respectively. These growth behaviors can be explained using arrangements of oxygen ions. Cross-sectional scanning electron microscopy shows that microstructures of the heterostructures depend on the substrates. It is found that the growth behaviors and the microstructure affect leakage current behaviors of the Bi4Ti3O12 layers. Ohmic and space-charge-limited conduction mechanisms are used to explain leakage current behaviors of the Bi4Ti3O12 film on La0.5Sr0.5CoO3/LaAlO3(001) and La0.5Sr0.5CoO3/Al2O 3(0001), respectively.