Dense (1−x)BiScO3–xPbTiO3 nanoceramics with morphotropic phase boundaries and an average grain size of 11nm were prepared. Synchrotron X-ray diffraction studies revealed that tetragonal and monoclinic phases coexist, and the grain boundary regions could be modeled as a paraelectric cubic phase. The grain boundary regions possessed complicated stress and electric fields. The polarization switching became more difficult under electric field due to the restriction and screening effect of grain boundary regions. The nanoceramics retained ferroelectricity with d33∗=292.9±29.8pmV−1 and d33=19.8pCN−1.