To　improve　the　ductility　of　bulk　electrodeposited　copper,　the　microstructural　(grain　size,　dislocation　defects　etc.)　evolution　and　the　mechanical　properties　of　the　bulk　copper　annealed　at　above　500°C　were　mainly　investigated.　The　results　showed　that　there　existed　normal　grain　growth　and　abnormal　grain　growth　in　the　samples　annealed　in　the　temperature　range　of　500~560°C.　After　annealing　at　530°C　for　2　h,　compared　with　the　sample　annealed　at　500°C,　the　strength　was　enhanced　abnormally,　but　at　the　same　time　the　ductility　remained.　The　abnormal　variation　of　properties　was　proved　to　be　related　to　the　uniform　multiscale　grain　structures　introduced　by　annealing　at　530deg;C　and　the　changes　of　dislocations　and　twins.　The　high　strength　derived　from　the　copious　boundaries　of　ultrafine　grains　which　could　hinder　the　movement　of　dislocations　and　the　ductility　originated　from　the　micron　grains　embedded　in　the　matrix　of　ultrafine　grains　which　could　contain　more　dislocations.　Meanwhile,　the　internal　dislocation　defects　decreased,　which　promoted　the　grain　to　further　bear　the　dislocation　generated　by　tensile　deformation　and　finally　improved　the　plasticity.　The　density　of　twin　and　the　thickness　of　twin　lamellar　relatively　increased.　Twin　boundaries　could　also　hinder　dislocation　motion　to　improve　the　strength　of　the　material.　The　thicker　twins　could　absorb　dislocations　to　improve　the　plasticity.　The　variation　of　twins　is　helpful　to　improve　the　mechanical　properties　of　the　materials.