The invention discloses a three-level quicklime hydrator, comprising a feeding port, a sealed conveyance section box body, a first hydration section box body, a water spraying device, a sealed dust removal cover, an upper hydration box body blanking position and material poking port, a second hydration section box body, a second hydration box body blanking position and material poking port, a third hydration section box body and a discharging port, wherein a pair of first stirring shafts with stirring blades is arranged in the first hydration section box body; the pair of first stirring shafts is driven by a first driving device, and the rotating directions of the first stirring shafts are opposite; a pair of second stirring shafts with stirring blades is arranged in the second hydration section box body; the pair of second stirring shafts is driven by a second driving device, and the rotating directions of the second stirring shafts are opposite; a pair of third stirring shafts with stirring blades is arranged in the third hydration section box body; the pair of third stirring shafts is driven by a third driving device, and the rotating directions of the third stirring shafts are opposite; and the sealed dust removal cover is provided with a dust collection external port.