Abstract: Solid waste from vanadium extraction contains sodium sulfate and ammonium sulfate. If not treated properly, it will pollute the environment and waste resources. The process of calcination-leaching-evaporation crystallization was designed to treat the solid waste by reducing mirabilite with pulverized coal. Thermodynamic software was used to calculate the theory of recovering sodium sulfide from solid waste of vanadium extraction. The effects of reduction time, leaching temperature and leaching time on product recovery and Na₂S content were studied. The optimal conditions are determined as following reduction time at 4 h, leaching temperature in 75 ℃, leaching time with 6h. Under these conditions sodium sulfide content of the product is 98.41%, and the yield of sodium sulfide is 97.71%.