The structural evolution and properties of 0.3Pb(In1/2Nb1/2)O-3-0.38Pb(Mg1/3Nb2/3)O-3-0.32PbTiO(3) (0.3PIN-0.38PMN-0.32PT) ferroelectric ceramics with different sintering times have been investigated. The content of the tetragonal phase is increased in samples sintered for more than 6h, despite that the composition falls in the rhombohedral region of the previously established phase diagram. The results show that the metastable tetragonal phase at room temperature is induced and stabilized by the tensile residual stresses. Excessively long sintering time generally leads to grain coarsening, loss of lead, and deterioration of properties, while the increasing amount of the tetragonal phase, and the large residual tensile stress appear to improve the dielectric and electromechanical properties. This study offers new insights into the sintering of Pb-based ferroelectric ceramics with complex compositions.