Lanthanum doped lead titanate (PLT) ferroelectric thin films were grown on Pt/Ti/SiO2/Si(100) substrates using RF magnetron sputtering. X-ray Diffraction (XRD) was applied to study crystalline properties of PLT films, and XRD patterns of PLT thin films show that there appeared (111) preferred-oriented tetragonal perovskite phase. The ferroelectric domain patterns and the corresponding topography of PLT thin films have been investigated using piezoresponse force microscopy (PFM) and atomic force microscopy (AFM), respectively. PFM observations show that there exist nanoscale banded 90° domain patterns 20 to 60 nm in width and low energy head-to-tail polarization configurations in PLT film. The relationship between fabricating conditions and properties of PLT10 thin films was studied. It was found that PLT10 thin film fabricated under the optimized conditions possess dielectric constant εr=365, dielectric loss tgδ=0.02, and pyroelectric coefficient γ=2.18×10-8C·(cm2·K)-1, respectively. The PLT thin films could meet the needs for uncooled pyroelectric infrared sensors.