The invention belongs to the technical field of a building material technology, and more specifically relates to a lightweight building fireproof insulation board. The fireproof insulation board comprises the following components: a gallant, vitreous beads, expanded perlite, floating beads, silicon dioxide, alumina powder, clay, calcium lignin sulphonate, polypropylene fiber, cement and water. Thegellant comprises the components of magnesium oxide and phosphate, the mesh number of the floating bead and the vitreous bead is 60-80 meshes, a particle size of the silicon dioxide is 1-2 mm, and aspecification of polypropylene fiber is 12-16 mm. A production method of the lightweight building fireproof insulation board comprises the following steps: pulping, casting, pressurization, moulding,vacuum treatment, high-pressure penetration of a fireproof filling paint, and drying and the like. The fireproof insulation board has the advantages of good insulation effect, high structural intensity, and excellent flame resistance, the material weight is light, and the transport cost and construction difficulty are low.