This　study　sought　to　analyze　the　effect　of　curing　temperature　on　mechanical　strength　and　microstructure　of　a　copper　tailing-based　geopolymer　via　scanning　electron　microscopy　(SEM),　HCl　extraction,　nuclear　magnetic　resonance　(NMR),　and　X-ray　diffraction　(XRD).　The　distribution　of　gel　formed　in　geopolymers　tended　to　be　uniform　with　increasing　curing　temperature　from　25　to　80　°C.　Moreover,　the　percentage　of　Si　sites　in　C–S–H　and　N-A-S-H　gels　increased　from　62.08%　to　78.94%　and　more　tetrahedral　[AlO4]　was　incorporated　into　the　tetrahedron　[SiO4]　backbone,　leading　to　an　increase　of　compressive　strength　from　10.2　to　39.6　MPa.　When　the　curing　temperature　was　increased　to　120　°C,　the　percentage　of　Si　sites　in　C–S–H　and　N-A-S-H　gel　decreased　to　69.52%,　and　the　compressive　strength　decreased　to　27.5　MPa.　Moderately　elevated　curing　temperature　promoted　the　dissolution　of　aluminosilicate　while　curing　temperatures　above　80　°C　hindered　it.　Excessive　curing　temperature　led　to　a　decrease　in　the　geopolymer　alkaline　medium.　©　2020　Elsevier　Ltd