To address the issues of low activity and difficult treatment of burnt coal cinder, the preparation technology and calcination effect of geopolymers based on burnt coal cinder were investigated, with the concept of low carbon and environmental protection as the core. The influence of calcination temperature, activator dosage and liquid-solid ratio on the compressive strength of geopolymers based on burnt coal cinder was investigated by single factor tests, and the optimal mix ratio was subsequently determined. Using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), the hydration products and micromorphology of geopolymers were studied. Revealing mineral phase changes during calcination and the geopolymerization process, and clarifying the mechanism of strength enhancement. The results indicate that the combined activation method with calcium oxide as the main and trisodium phosphate dodecahydrate (TSPH) as the auxiliary was successfully employed to prepare the geopolymers with a compressive strength of 34.5 MPa at 28 days. The alkaline environment and nucleation sites provided by calcium oxide, along with the phosphate radicals supplied by TSPH, all contribute to the dissolution of active components in the burnt coal cinder and the formation of complex gel phases, which is an important source of compressive strength for geopolymers. Furthermore, at calcination temperatures of 1 000 ℃, burnt coal cinder lacks the thermal activation property of solid wastes such as coal gangue and fly ash, and high-tempera ture calcination diminishes its chemical reactivity.