Materials with negative permittivity need to be used at different temperatures, while the negative permittivity behavior affected by large fluctuations in temperature has seldom been studied. In this work, La0.5Sr0.5MnO3 ceramics were prepared by a sol-gel auto-combustion method and subsequent sintering. The negative permittivity behavior, electrical conductivity and reactance of La0.5Sr0.5MnO3 ceramics were systematically studied at various temperatures. The fluctuation in negative permittivity is less than 2.6 % and the dielectric loss (tanδ) is less than 0.2 in the temperature range of 50–600 °C. Based on the key governing properties being achieved, the present work experimentally demonstrates that La0.5Sr0.5MnO3 ceramics, as single-phase oxides, can be used as a feasible alternative metamaterial in a wide temperature range.