Abstract: The strength test of a new steel slag-based filling cementitious material was carried out with a high-mud tailings as aggregate. Under the same conditions of cement-sand ratio and slurry concentration，the strength of the high-mud full tailings backfill is significantly higher than that of 42.5 cement， and the cost is lower. On this basis，the pipeline transportation characteristics test of high-mud full tailings filling slurry with different slurry concentration and cement-sand ratio was carried out，including the flow parameters and stability parameters of the slurry，and the mathematical model of the pipeline transportation characteristics of the filling slurry was established. The results show that when the slurry concentration increases，the consistency，bleeding rate and stratification of the filling slurry gradually decrease. When the cement-sand ratio increases，the slurry consistency gradually increases，while the bleeding rate gradually decreases.

Key words: back-filling method, steel slag-based cementitious material, high-mud full tailings, pipeline transportation characteristics