The crystalline grains of Bi4Ti3O12 thin films are tended to c-axis-orientation in a usually deposited process on planar substrates, but the piezoelectric and ferroelectric storage devices largely utilize the a-axis-oriented component of spontaneous polarization. So, it is importance to investigate the way to gain a-axis-oriented Bi4Ti3O12 thin films. The polycrystalline Bi4Ti3O12 thin films successfully prepared by femtosecond laser deposition on Si(111) wafers are reported in this paper. The structural properties and crystallographic orientation of the films were investigated by X-ray diffraction (XRD) method in 2θ only scan, the surface morphology of the films was observed using the field scanning electron microscope (FSEM). The Bi4Ti3O12 thin film deposited at room temperature (20 ℃) was highly c-axis-oriented; but the film deposited at 500 ℃ was highly a-axis-oriented. It was observed that the films were composed of well-distributed grains, the grains of the 20 ℃-sample was about 20 nm in diameters, the grains of the 500 ℃-sample was 30～200 nm, large particles (≥1 μm) were not found in the surface of the two samples. A Fourier-transform infrared spectroscopy (FT-IR) was used to measure the transmittance and reflectance of the film deposited on quartz at room temperature, and then to determine the optical forbidden gap of the film, the optical forbidden gap of it was 1.0 eV. The remnant polarization (Pr) of the a-axis-oriented sample was measured to be 15 μC/cm2 by RT-66A the coercive force (Er) was 48 kV/cm.