Steel slag powder, S95 mineral powder, fly ash and desulfurization gypsum were used as raw materials, and multifaceted solid waste cementitious materials were prepared through the optimized design of the simple shape center of gravity method. The effect of composition on the mechanical properties of solid-waste mortar was analyzed by compressive and flexural strength tests of the mortar. X-ray diffraction (XRD), Fourier infrared spectroscopy (FT-IR) and thermogravimetric (TG) methods were used to investigate the strength formation mechanism of the multifunctional solid waste-based cementitious materials. The results show that the optimal mixing ratio of multifunctional solid waste-based cementitious materials is steel slag powder: S95 mineral powder: fly ash： desulfurization gypsum=31:38:27:4. The mechanical properties of multifunctional solid waste-based glued sand specimens show a tendency to increase and then decrease with the increase of steel slag powder admixture. S95 mineral powder contributed more to the early strength of the glued sand specimens, while excessive fly ash admixture is detrimental to the formation of the strength of the glued sand. The infrared absorption peak of SFMD showed the telescopic vibration peak of Si—O in C-S-H at 969 cm^-1, and the weight loss of C-S-H in SFMD is the most, which indicated that the synergistic effect among the components of the system is better. In addition, desulfurization gypsum can induce a more complete synergistic hydration reaction of the steel slag powder-S95 mineral powder-fly ash system to produce caliche that provides strength.