In order to enhance the resource utilization of molybdenum tailings sand (MTs) and reduce the production cost of self-compacting concrete (SCC), the effect of MTs replacement rate on the working performance and mechanical performance of SCC under different sand rate was studied, and the resulting environmental and economic benefits were analyzed. The results show that the working performance of SCC decreases with the increase of MTs replacement rate, but SCC with good filling, gap passage and anti-segregation properties could be prepared by modulating the slump extension degree by changing sand rate and water reducer dosage. At 46% and 50% （mass fraction） sand rate, when the MTs replacement rate are 30% and 20% (mass fraction), the negative pore (less harmful holes, harmful holes and more harmful holes) percentage of SCC reduces and the compressive and splitting tensile strength significantly enhance. In addition, the incorporation of MTs effectively enhances the environmental and cost benefits. Considering the effects of MTs on the working performance, compressive strength, environment benefits and economic benefits of SCC, the study concludes that it is optimal to use 46% sand rate and 30% MTs replacement rate to prepare SCC in the neighboring areas where molybdenum tailings are abundant.