Desulfurized gypsum industrial waste slag molding external light stone, by weight percentage, desulfurized gypsum 40.0% ~ 50.0%, magnesium oxide 29.85% ~ 40.25%, magnesium sulfate 10.0% ~ 15.0%, citric acid 0.15% ~ 0.25%, water reducing agent 0.10%-0.25%, polymer powder, 0.50%-0.80%, fiber 2.50%-3.20%, pigment 0.5%-1.0%; the magnesium oxide is selected from the industrial grade purity with calcination temperature of 400 degrees and mesh number of 400 It is more than 90% white powder. It improves the water resistance of magnesium oxysulfate cement and the toughness and strength of artificial stone. It contains a large number of micropores, which greatly reduces the density of artificial stone and realizes the multi-functionality of artificial stone such as thermal insulation, humidity control and sound insulation. Realize the recycling of industrial waste, the safe and reliable treatment of industrial waste desulfurization gypsum, and the utilization rate is as high as 40%.