Ternary perovskite-type solid solutions of Pb(Zr x Ti 1 - x ) 1 - y (Mg 1 / 3 Nb 2 / 3 ) y O 3 (PZTMN) were synthesized by wet-dry combination method in which a wet-process was applied to B-site cations. These solid solutions had no compositional fluctuation and high density. Their dielectric constant and electromechanical planar coefficient (k p ) were higher than those of PZTMN prepared by the conventional dry method. Moreover, their compositional dependence of k p exhibited a peak at the morphotropic phase boundary, while PZTMN prepared by the dry method did not.