Aiming at the characteristics of structural backfill engineering, combined with the backfill performance requirements of subway stations, and taking backfill material fluidity, crystalline body strength, seepage resistance and volumetric stability as the main assessment indexes, a self-compacting and high seepage-resistant backfill material has been researched and prepared by taking the bulk solid waste cinder slag and fly ash as the main raw materials, blast furnace slag powder as the dope, and cement as the curing component. Compared with traditional backfill, the material has self-leveling characteristics and good backfill uniformity. The 28-day compressive strength of the material can reach 10.2–21.3 MPa, which exceeds that of C10 concrete. The material has good seepage resistance, seepage pressure up to 0.7–0.8 MPa, good volume stability, 28 d shrinkage rate of 10–4 orders of magnitude. The research results were applied in the backfilling project of Xintun Station of Qingdao Metro Line 6, which showed excellent mobility, greatly saving construction cost and time, and the test results met the project requirements. This study takes into account the requirements of material performance and the proportion of solid waste mixing, and under the premise of meeting the engineering requirements of backfill materials, it can effectively absorb fly ash, slag and other bulk solid waste, and has achieved good economic and environmental benefits.