The invention discloses a fume desulfurization absorber, comprising a tower body, a fume outlet on the top of the tower body, a slurry pool for housing the desulfurization scrubber on the bottom of the cavity of the tower body, a scrubber sprinkler pipe horizontally set below the fume outlet in the tower body and communicated with the slurry pool by a circulating pump; a fume inlet below the scrubber sprinkler pipe in middle of the tower body, wherein at least part of the tower body uses an expanding bell mouth structure with gradually increasing ring diameter along the downward direction andthe fume inlet is on the expanding bell mouth structure and the expanding bell mouth structure eliminates the inlet inclination-angle of the absorber and fume inlet pipe of the absorber is changed into horizontal, therefore the design difficulty is reduced, the material requirement of the project is saved, the pressure loss of the inlet segment is reduced, the optimization design is optimized, theconstruction work cost is reduced and the absorber run energy consumption is reduced.