Abstract: The optimal ratio was obtained by range analysis of orthogonal test , and based on the optimal ratio, the content of GGBS was substituted by different content of steel slag , and those samples were characterized by compressive strength test , water absorption test and expansion-contraction test , the influence of steel slag substitution on the physical and mechanical properties of samples were analyzed . Studies have shown that:steel slag substitution have a significant impact on the physical and mechanical properties of samples , with the substitution of steel slag increased , the compressive strength of samples gradually reduced , water absorption gradually increased , shrinkage rate decreased; with the substitution of steel slag increased , plomberite-14A, xonotlite, hydrocalumite and C-S-H gradually reduced until disappeared , while plate-shaped hydration products gradually increased .

Key words: steel slag;cementitious backfill material;mechanical property;microstructure analysis