Abstract: BiScO₃-xPbTiO₃-yPb(Yb_1/2Nb_1/2)O₃ (BS-xPT-yPYN,y=0.10,0.15,0.20, 0.30) piezoelectric ceramics were prepared by the precursor method. The effects of PYN molar fraction y on the microstructure, phase composition, phase structure, ferroelectric and piezoelectric properties of BS-xPT-yPYN ceramics were investigated. The results indicate that when y increased, the grain size of piezoelectric ceramics increased, the transformation from rhombohedral phase to tetragonal phase took place and the piezoelectric properties declined. When the molar fraction of PYN was 0.10, the higher coercive electric field E_c, the more obvious increase residual polarization P_r of piezoelectric ceramics had.