5-inch diameter Bi3.15Nd0.85Ti3O12 (BNT) ferroelectric thin films were prepared on Si wafers by a modified pulsed laser deposition method, in which two laser scanning rates and 6-inch diameter target were used. The investigation on the distribution of the film thickness reveals that the laser scanning technique used in conjunction with the large-diameter target can improve the uniformity of film thickness. Especially the reasonable setup of the laser scanning rate ablating the fringe area of the large target has a prominent effect on weakening the edge deviation of thickness distribution. Such phenomenon was fundamentally explained by the simulation results on the ablation tracks of the laser beam on target. Through optimizing the laser scanning rates, BNT thin film with uniform thickness was obtained on 5-inch diameter Si wafer and the maximum variation in film thickness was found to be less than +/- 2.5%. The results of X-ray photoelectron spectroscopy and X-ray diffraction show that the prepared 5-inch BNT thin film has great uniformity in stoichiometry and crystallinity. In addition, the measurements of electrical properties indicated that the prepared BNT thin film exhibits good ferroelectric property and I-V characteristic. (C) 2015 Published by Elsevier B.V.