Sm-doped bismuth titanate and random oriented Bi4-xCexTi3O12 (BCT) thin films were fabricated on Pt/Ti/SiO2/Si substrates rf magnetron sputtering technique. The structures and the ferroelectric properties of the films were investigated. Ce doping leads to a marked improvement in the remanent polarization (Pr) and the coercive field (Ec). At the applied electric field of 100 kV/cm, Pr and Ec of the BCT (x = 0.8) film annealed at 650 oC are 20.5 μC/cm2 and 60 KV/cm, respectively. However, after 3 × 1010 switching cycles, 20% degradation of 2Pr is observed in the film.