Effects of additives Li2CO3, Ag2O, NiO, Cr2O3, Fe2O3, Gd2O3, Bi2O3, TiO2, MnO2, Nb3O5 and WO3 on piezoelectric and related properties of PbTiO3 ceramics are studied. Additives partly dissolve in lattice and the rest segregate at grain boundary. These additives act as grain growth inhibitors and binders. Additions of Li2CO3, NiO, Fe2O3 and MnO2 are most effective for densification. The additives Gd2O3, Bi2O3, Nb2O5 and WO3 give high resistivity probably by compensating Pb vacancies. Many piezoelectric and related properties depend on species and content of additives. Grain size is a main factor influencing these properties. The specimens with Cr2O3 and MnO2 characterized by coarse grain have small ε*, small dissipation factor, short poling time, large coupling factors, high mechanical Q and small elastic compliance. These features may be explained by diminishing of stress between grains, decrease of interfacial polarization and large binding force at grain boundary.