In　this　paper,　a　very　simple　method　was　used　to　synthesize　ligand-free　luminous　hydrogels　doped　with　Tb3+　and　Eu3+.　The　hydrogels　exhibit　red　(615　nm),　green　(544　nm)　and　blue　(425　nm)　emissions　derived　from　Tb-3,　Eu3+　and　defects,　respectively.　Effective　energy　transfer　from　Tb3+　to　Eu3+　is　observed.　We　apply　these　ligand-free　luminous　hydrogels　for　temperature　sensing　for　the　first　time.　In　surprise,　the　relative　sensitivities　are　all　very　high　(＞2　%/K)　by　using　many　kinds　of　fluorescence　intensity　ratios.　In　addition,　with　the　increase　of　temperature,　the　emission　color　of　the　samples　changes　significantly　(from　orange-red　to　blue)　which　can　be　applied　for　visual　temperature　sensing.　The　above　results　infer　that　the　ligand-free　luminous　hydrogels　can　be　used　as　an　eco-friendly　visual　temperature　sensing　material.