High-Q Li2MgxTiO3+x (2.2 <= x <= 4) microwave dielectric ceramics were fabricated by using a conventional solid-state reaction method followed by laminated sintering technique. All samples showed clear and smooth grains through this sintering method. The XRD patterns indicated that Li2MgxTiO3+x (2.2 <= x <= 4) ceramics displayed MgO-like cubic phase with ordered rock salt structure. The dielectric constant decreased monotonically because the molar volume expanded and molecular polarizability decreased when x values increased. The Q x f values of Li2MgxTiO3+x (2.2 x 5 4) ceramics were dependent significantly on both average grain sizes and packing fraction. The Li2Mg3.6TiO6.6 ceramics sintered at 1375 degrees C had excellent microwave dielectric properties of epsilon(r) similar to 12.7, Q x f 169,000 GHz, tau(f) similar to -32.8 ppm/degrees C.