The Bi4Ti3O12 and Bi3.25La0.75Ti3O12 thin films are prepared on the Pt/Ti/SiO2/Si substrate using sol-gel method. The structures Pt/Bi3.25La0.75Ti3O12/Pt and Pt/Bi4Ti3O12/Pt are fabricated. The effects of La doping on the microstructures, and ferroelectric properties of Bi4Ti3O12 films are investigated. The 2Pr with test voltage 6V for the sample annealed at 700℃ increased from 12.5 μC/cm2 to 18.6 μC/cm2, and 2Vc is still 2.8 V when the La3+ ions occupy part of Bi3+ sites. The Bi3.25La0.75Ti3O12 films showed fatigue-free behavior. The mechanism of improvement of La-doped Bi4Ti3O12 ferroelectric thin films is discussed.