An organic medium resistant styrene butadiene rubber vulcanized rubber and a preparation method thereof are characterized in that: by a double coupling alternate addition mode, a clay/nano-calcium carbonate hybrid filler is prepared; and further by the prevulcanized part crosslinking-stress network compression- vulcanization fixing moulding process, the organic medium resistant styrene butadiene rubber vulcanized rubber having good filler-rubber interaction, effective organic solvent barrier layer and small cross-linked network molecular gap is obtained.