Nanoscale characterization of fieldinduced displacement was made in compositionally graded PZT thin film according to the inverse piezoelectric effects by SFM in contact mode. The nanoscale piezoelectric displacement  electric field butterfly loop was obtained due to the combined contribution from linear piezoelectric effect and domain switching effect, which substantiate nanoscale validity of CaspariMerz theory. The nanoscale imprint phenomena were also observed in the thin film.