The ternary ferroelectric ceramics Pb(Yb1/2Nb1/2)O-3-Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PYN-PMN-PT), in the vicinity of morphotropic phase boundary (MPB) region, have been prepared by a two-step synthetic process. The ternary phase diagram at room temperature has been established based on the XRD data analysis, which exhibits a curved MPB region. The dielectric, ferroelectric and piezoelectric properties have been characterized, indicating the electrical properties can be adjusted regularly by choosing compositions. The Curie temperature T-C of ternary system varied from 165 to 370 degrees C. With the increase of PMN content, the piezoelectric coefficients d(33) increase from 373 to 505 pC/N, and the coercive field E-c decrease from 18 to 6 kV/cm. The results show that the PYN-PMN-PT ternary system can be a potential material for high temperature applications. (C) 2012 Elsevier Ltd. All rights reserved.