Molten iron desulphurization slag/styrene butadiene rubber composites were prepared using molten iron desulphurization slag as rubber filler to replace part of carbon black. The effects of molten iron desulphurization slag/carbon black ratio(by mass),particle size of molten iron desulphurization slag, curing system and curing time on the mechanical properties of the molten iron desulphurization slag/styrene butadiene rubber were studied. The results show that the mechanical performance and economic benefits of the molten iron desulphurization slag/styrene butadiene rubber are the optimal when the molten iron desulphurization slag/carbon black ratio is 20/30, the particle size of the molten iron desulphurization slag is 16μm(1000mesh), the curing system is the promoter N tert butyl 2 benzothiazole sulfenamide and the sulfur(ratio of the promoter NS and the sulfur is 100/175), and curing time is about 1500s.