Inorganic oxide ceramics are essential for microwave applications due to their stable structure and exceptional performance. LiZnMgGaTi2O8 ceramics were prepared using the solid-phase method. XRD and TEM confirmed that the ceramics possess spinel structures. The ceramics had a maximum relative density of 94.57 % and a Vickers hardness of 8.58 GPa when sintered at 1220 °C. The ionic polarizability of Ti4+ in the ceramics exceeds the Shannon value, leading to a 20.3 % deviation between εth and εr. The activation energy of the impedance spectrum fitting is 1.302 eV, indicating a low concentration of oxygen vacancies in the ceramic. Hence, the Q × f value of the ceramics is primarily influenced by relative density. The optimal microwave dielectric properties of LiZnMgGaTi2O8 ceramics are εr = 15.68, Q × f = 66,620 GHz, and τf = −30.9 ppm/°C. The test curves of εr and dielectric loss remain nearly parallel to the x-axis from −80 °C to 80 °C, demonstrating the excellent stability of LiZnMgGaTi2O8 ceramics.