The invention discloses a fireproof insulation board. The fireproof insulation board comprises an insulation board body, wherein a surface layer is arranged on the surface of the insulation board body, a first fireproof layer is arranged between the insulation board body and the surface layer, a second fireproof layer is arranged inside the insulation board body, the back of the insulation board body is in a sidestep shape, and partitioning lines among steps are in a convex arc shape. The fireproof insulation board disclosed by the invention has the advantages that two fireproof layers are added, fireproof and heat insulation effects are good, no deformation is produced, and service life is long; and the back of the insulation board is in the sidestep shape, is tightly combined with a wallbase and does not slide down, and the construction is safe, rapid and convenient.