Abstract: Objective In order to improve the utilization efficiency of tailings and reduce the environmental problems caused by tailings storage, this article focuses on molybdenum tailings as the main research object, and couples molybdenum tailings with slag powder to prepare cement-based materials. Method Based on the study of the basic physicochemical properties of molybdenum tailings, the effects of different proportions of molybdenum tailings and slag powder on the mechanical properties of colloidal sand test block were investigated. The hydration products and microstructure of the hardened slurry were analyzed by XRD, TG, IR and SEM. Result Molybdenum tailings are mainly composed of silicon and aluminum, and the mineral components are mainly plagioclase, pyroxene and hornblende. The 28 d activity index of molybdenum tailings is 67%. When the mass ratio of slag powder and tailings is 2∶1, the 28 d compressive strength of the mortar test block is 55.2 MPa, and the contribution rate of activity is 45.3%. Conclusion The hydration products of hardened paste are mainly C-(A)-S-H gel and Ca(OH)₂. With the increase of age, the hydration products increase, the structure of hardened paste gradually becomes dense, and the strength increases.