Nb　and　Ni　co-doped　CaCu3Ti4O12　ceramic　samples　(CaCu2.8Nb0.2Ti3.9Ni0.1O12)　were　obtained　via　the　solid-state　reaction　method.　We　focused　on　the　effect　of　sintering　temperature　(1020°C,　1040°C　and　1060°C　for　6　h)　on　phase　compositions,　microstructure,　impedance　and　dielectric　properties.　X-ray　diffraction　(XRD)　studies　confirmed　the　constitution　of　a　body-centered　cubic　perovskite　structure.　Scanning　electron　microscopy　(SEM)　micrographs　revealed　that　average　grain　size　increased　with　the　rise　of　temperature.　Dielectric　properties　ranging　from　103　Hz　to　106　Hz　were　tested　at　room　temperature.　CaCu2.8Nb0.2Ti3.9Ni0.1O12　sample　sintered　at　1040°C　attained　the　highest　dielectric　constant,　whereas　the　sample　sintered　at　1060°C　achieved　effective　frequency　stability　for　dielectric　constant　along　with　the　smallest　grain　resistance　Rg.　The　sample　sintered　at　1060°C　possesses　the　lowest　dielectric　loss　and　maintains　a　high　dielectric　constant;　thus　it　has　optimal　comprehensive　dielectric　properties.　©　2021　IEEE.