With the molten iron desulphurization slag as research object, the molten iron desulphurization slag / styrene butadiene rubber was prepared by using molten iron desulphurization slag as rubber filler instead of partial carbon black compound styrene butadiene rubber. The performance of molten iron desulphurization slag/styrene butadiene rubber was tested with various methods while the structure of molten desulphurization slag was tested with Fourier transform infrared spectrometer during the different periods of curing process. The results showed that the effect of strengthening and reducing the cost of reinforcing agent can be achieved by using molten iron desulphurization slag instead of partial carbon black. The optimum cure time of molten iron desulphurization slag / styrene butadiene rubber (t90) was 25.08 min, the scorch time was 0~15 min, the thermal curing period was 15~25 min, the curing flat period was 25~45 min. The molten desulphurization slag could provide alkali environment during the scorch time, which was beneficial to increase the liquidity of styrene butadiene rubber. During the thermal curing period and curing flat period, the Ca2SiO4 in the molten desulphurization slag could continue to accelerate the hydration reaction to generate C—S—H gel, which could achieve the effect of strengthening styrene butadiene rubber. In addition, molten desulphurization slag could avoid the emergence of over curing period of molten desulphurization slag/styrene butadiene rubber.