The effects of polymer-binder ratio and slag content on the strength properties of autoclaved SBR-modified concrete using ground granulated blast-furnace slag and styrene-butadiene rubber latex are examined. As results, the compressive and tensile strength of the autoclaved SBR-modified concrete using slag are higher at a slag content of 40%, and are increasing according to polymer-binder ratio. In particular, the autoclaved SBR-modified concrete with a slag content of 40% is about three times higher tensile strength than unmodified concrete. Such a high strength development is due to the improved bond between cement hydrates and aggregates because of the incorporation of SBR latex. From the point of deteriorated physical properties and changed infrared spectra, the application of autoclaving under saturated $Ca(OH)_2$ solution immersion causes no degradation for SBR polymer films.