Molybdenum tailings are difficult to develop and utilize because of their high crystallinity mineral phase and low-grade metal elements. In order to realize the resource utilization of molybdenum tailings, based on the mineralogical characteristics of molybdenum tailings, the effects of heat treatment temperature and time on the phase composition and microstructure were studied, and the thermal activation modification mechanism of molybdenum tailings was developed. Based on the optimal heat treatment temperature, molybdenum tailings based alkali-activated geopolymer (AAG) cementitious material was successfully prepared, and the effect of heat treatment time on its curing time and compressive strength was studied. The results show that heat treatment at 850 ℃ for 2 h promotes the decomposition of muscovite and calcite in molybdenum tailings, and some low crystalline garnet and quartz phases transforme into amorphous aluminosilicate (ferrite), which significantly improve the content of active silicoaluminate in molybdenum tailings. The surface roughness of molybdenum tailings particles increases with the increase of heat treatment time, and the pozzolanic activity is significantly improved. The curing time of AAG prepared by molybdenum tailings after heat treatment at 850 ℃ for 2 h is shortened to 48 h from 168 h, which is significantly lower than that of AAG with untreated molybdenum tailings at room temperature, and the compressive strength after curing for 14 d increases by 2 times, reaching 35.7 MPa. The research results greatly broaden the raw material sources of geopolymer, and provide a feasible modification scheme for the utilization of molybdenum tailings.Key words: