This invention is related to a slurry filtration device and the wet lime-gypsum flue-gas desulfurization system comprising a slurry filtration device for the separation (concentration) of gypsum. The slurry filtration device comprises tank that has a slurry supply pipe at its upper part and a filtrate-drain hole at its bottom, a layer of filter sand lying on its bottom, a slurry accumulator arranged on the layer of filter sand, and a vibrator set in said slurry accumulator for vibrating the slurry. The present invention not only improves the solid-liquid separability remarkably but also saves cost and space.