Ultrafine (1-x)BiScO3-xPbTiO3 ferroelectric ceramics were successfully prepared by employing nanocrystalline ceramic powder. The average ceramic grain sizes range from 0.4μm to 1.2μm with different phases and different proceeds. The studies show the average grain sizes vary with the calcining and sintering temperature as well as the compositions in different phases. Ceramics, sintered at 1020°C for 3h, in morphotropic phase boundary (MPB) have the smallest grain sizes around 0.4 μm, those in tetragonal phase and rhombohedral phase have larger grains around 0.9μm. Meanwhile, the piezoelectric property and Curie temperature were founded size-dependent when the grain sizes are smaller than 1μm.