CaCu3Ti4O12　(CCTO)　is　a　potential　dielectric　material　with　giant　permittivity,　good　stability　over　the　wide　temperature　and　frequency　range.　However,　the　dielectric　responses　of　CCTO-based　ceramics　are　mainly　investigated　in　the　frequency　of　10(2)-10(6)　Hz,　which　is　far　low　to　clarify　the　intrinsic　dielectric　feature.　So,　microwave　dielectric　properties　have　been　investigated　for　the　CCTO　porous　ceramics　sintered　at　low　temperature　(＜=　1000　degrees　C).　Good　microwave　dielectric　properties　of　permittivity　epsilon　=　62.7,　quality　factor　Qf　=　3062　GHz　and　temperature　coefficient　of　the　resonant　frequency　tau(f)　=　179　ppm/degrees　C　are　achieved　for　the　CCTO　ceramics　sintered　at　1000　degrees　C,　the　dielectric　loss　significantly　decreases　two　orders　to　0.002　compared　to　that　of　CCTO　ceramics　sintered　at　critical　temperature　of　1020　degrees　C　confirmed　by　differential　scanning　calorimetry　(DSC).　This　clue　indicates　that　giant　permittivity　and　high　loss　is　not　intrinsic　for　CCTO　ceramics,　but　derives　from　composition　segregation,　liquid　phase　and　defects　associated　with　internal　barrier　layer　capacitor　(IBLC).　It　suggests　that　CCTO-based　ceramics　is　a　promising　microwave　dielectric　materials　with　high　permittivity.