Abstract: In order to solve the problem of resource utilization of molybdenum tailings, molybdenum tailings powder is prepared from molybdenum tailings of Yichun Luming Mining. The influence of molybdenum tailings powder as admixture on the working performance, mechanical strength and microstructure of cement-based materials is studied through the performance indexes of standard consistency water consumption, setting time, fluidity, strength, activity index, microstructure and hydration products. The results show that the addition of molybdenum tailings powder increases the standard consistency water consumption by 3.2%, and the initial setting time and final setting time are prolonged by 75% and 93% respectively. The addition of molybdenum tailings powder reduces the fluidity of mortar, increases the water demand ratio of mortar and reduces the 60 min in fluidity of mortar over time. With the increase of molybdenum tailings powder replacement rate, the flexural strength, compressive strength and activity index of mortar decrease gradually, but the activity index of mortar at 7 d and 28 d is more than 60%. When the replacement rate of molybdenum tailings powder is 30%, the microstructure of the paste has less pores, but the internal structure is denser. Besides hydration products such as ettringite and calcium hydroxide, the paste also contains minerals in molybdenum tailings powder such as SiO₂, feldspar and mica. The test results can provide basic test data for molybdenum tailings as admixture of cement-based materials.