In order to solve the problems of large storage area of ferrochrome slag, pollution of soil and water bodies, and low level of resource utilization, a new filling material of quaternary system was prepared by synergistic excitation of slag-lime-desulfurization gypsum-cement clinker to reveal the changes of rheological properties and mechanical properties of the slurry, combined with scanning electron microscopy to elaborate the hydration mechanism of the filling body, and the mechanism of curing/stabilization of the filling material was investigated by toxic leaching test. The results showed that the rheological curves of the slurry conformed to the Hershel-Bulkley model, and the yield stress of the slurry decreased significantly with the increase of superplasticizer dosing, and the dosing of ferrochrome slag was a non-significant factor affecting the change of yield stress of the slurry. The compressive strength of the filling body tends to decrease with the increase of chromium-iron slag doping; the compressive strength tends to rise and then decrease when the water reducing agent dosing increases from 0.1% to 0.4%; the early strength tends to rise and the later strength tends to rise and then decrease when the desulfurization gypsum dosing increases; the compressive strength tends to rise rapidly when the lime dosing increases from 5% to 20%, and The larger the doping amount is, the more obvious the rise is. The compressive strength reached the optimum value when the dosing of ferrochrome slag:slag:lime:desulfurization gypsum:cement:superplasticizer was 30:30:20:8:12:0.3. The microstructural morphology of the filler is dominated by columnar calcium alumina and agglomerated C-S-H gel, both of which are closely bonded to form a strong whole. The toxic ion leaching concentration of the 28-d hydration filler met the requirements of GB 8978-1996 "Integrated Wastewater Discharge Standard", and had significant solidification/stabilization effects on Cr3+ and Cr6+.