Abstract: In order to enrich the preparation materials of geopalymer, and broaden the utilization way of sludge and coal gangue, the authors used thermally activat ed sludge and coal gangue to prepare the geopolymer under the condition of alkaline excitation.The XRD, SEM, FT-IR were used to analyse the geopolymerOs macrosc opic and microscopic properties.The results showed the compressive strength of the geopolymer could reach 39.8 MPa, prepared with 40% thermally activated sludge (