Bi3.25 La0.75 Ti3 O12 (BLT) thin films were prepared on Pt/Ti/SiO2/Si substrate by the sol-gel method. The effect of annealing on their structures and ferroelectric properties was investigated. The XRD patterns indicate that the BLT films annealed at different temperatures are randomly orientated and the single perovskite phase is obtained at 550 ℃ . The remnant polarization increases and the coercive field decreases with the annealing temperature increasing. The leakage current density of the BLT films amealed at 700 ℃ is about 5.8 × 10-8 A/cm2 at the electric field of 250 kV/ cm.