Taking the content of calcium carbide residue, desulfurization gypsum and steel slag as the influencing factors, and the compressive strength of 7d and 28d as the response value, the response surface method (RSM) was used to study the influence of each solid waste interaction on the strength of fly ash geopolymer. The enhancement mechanism was analyzed by hydration heat, SEM and XRD tests. The results show that the contents of calcium carbide residue, desulfurized gypsum and steel slag optimized by RSM are 6.34%, 1.6% and 29.47% respectively, and the compressive strength of 7d and 28d reaches 18.10MPa and 29.92MPa respectively. calcium carbide residue-desulfurization gypsum-steel slag modified geopolymer will generate more C-(A)-S-H gel and ettringite (AFt) crystals. With the increase of curing age, the gel gradually increases, filling the tiny pores, making the structure more dense and the strength improved.