CuO-doped CaSiO3-1 wt% Al2O3 ceramics were synthesized via a traditional solid-state reaction method, and their sintering behavior, microstructure and microwave dielectric properties were investigated. The results showed that appropriate CuO addition could accelerate the sintering process and assist the densification of CaSiO3-1 wt%Al2O3 ceramics, which could effectively lower the densification temperature from 1250 1C to 1050 1C. However, the addition of CuO undermined the microwave dielectric properties. The optimal amount of CuO addition was found to be 0.8 wt%, and the derived CaSiO3-Al2O3 ceramic sintered at 1100 1C presented good microwave dielectric properties ofεr ? 7.27, Q ? f ? 16,850 GHz andτf ? ? 39.53 ppm/1C, which is much better than those of pure CaSiO3 ceramic sintered at 1340 oC (Q ? f ? 13,109 GHz). The chemical compatibility of the above ceramic with 30 Pd/70 Ag during the cofiring process has also been investigated, and the result showed that there was no chemical reaction between palladium-silver alloys and ceramics.