Method used for high-temperature liquid core mold dismantling of large-scale extra-thick plate blank

The invention discloses a method used for high-temperature liquid core mold dismantling of a large-scale extra-thick plate blank. The method is characterized by comprising the following steps of: pouring molten steel into a large-scale extra-thick plate blank mould cavity; performing high-temperature liquid core mold dismantling 0.5-3 hours after the pouring operation is finished; and cooling the large-scale extra-thick plate blank until the large-scale extra-thick plate blank is completely solidified. The method used for the high-temperature liquid core mold dismantling of the large-scale extra-thick plate blank, disclosed by the invention, removes shrinkage cavities and unconsolidated defects inside the large-scale extra-thick plate blank and hot cracks on the outer surface of the large-scale extra-thick plate blank.