The invention relates to a dual organic modified cement-base expanded perlite fireproof thermal-insulation board and a preparation method thereof. The dual organic modified cement-base expanded perlite fireproof thermal-insulation board mainly comprises the following components in percentage by weight: 50-80% of organic modified expanded perlite, 20-35% of Portland cement, 5-10% of polymer emulsion, 0-3% of active filler and 0.5-1% of additive. The preparation method comprises the following steps: evenly mixing raw materials, adding water, stirring to obtain a semidry material, filling the semidry material into a mold, compacting into a fireproof thermal-insulation board, and finally, carrying out high temperature steam curing for several hours. The dual organic modified cement-base expanded perlite fireproof thermal-insulation board not only has the advantages of strong deformation resistance, favorable crack resistance, shock resistance, favorable weather resistance, long service life, favorable fire resistance (Grade A) and the like in the Portland cement-base expanded perlite inorganic thermal-insulation board, but also has the advantages of high strength, low density and low elastic modulus. The invention has the characteristic of high production efficiency, and can implement large-scale production.