The (1−x)MgTiO3(MT)–x(Ca0.8Sr0.2)(Zr0.1Ti0.9)O3(CSZT) ceramic system prepared by using the conventional solid state method was investigated in terms of its microstructures and microwave dielectric properties. To achieve a temperature-stable material, two compounds with negative and positive temperature coefficients were used to form mixed phases. The microwave dielectric properties are strongly correlated with composition. For practical application, a dielectric constant (εr) of 22.1, a quality factor (Q×f value) of 116,000GHz, and a temperature coefficient of resonant frequency (τf) of 5ppm/°C for 0.95MgTiO3–0.05(Ca0.8Sr0.2)(Zr0.1Ti0.9)O3 sintered at 1300°C for 4h are proposed.