Cu-doped CaTiO3-based polycrystalline ceramics have been prepared by the conventional solid-state sintering. Our results indicate that the dielectric constant can be enhanced greatly by increasing the Cu-doped content, which show weak frequency and temperature dependence. The fitted activation energy is almost same (similar to 0.10 eV) as the Cu-doped content is 0.4-0.6, which may be ascribed to the first ionization of the oxygen vacancies. The origin of the high dielectric permittivity observed in these Ca1-xCuxTiO3-based ceramics should be attributed to the interfacial polarization mechanism, and can be well described by the percolation theory with f(c)approximate to 0.27 and s approximate to 0.74.