The invention relates to the field of vacuum metallurgy, in particular to a method for preparing a large-capacity (0.5 T) calcareous crucible for a vacuum induction furnace. The method comprises the following steps: firstly, preparing a common carbon-steel sealed bottom lining barrel in accordance with the capacity size of the crucible according to the specific size of a coil (0.5 T); then, mixing CaO sand evenly, tamping a bottom part and a wall part of the crucible by adopting a dry-wet combination method till 100 millimeters higher than a clarified liquid level of an alloy material for sintering, and tamping an MgO fireproof material upwards to a furnace mouth, comprising the furnace mouth by adopting the prior MgO crucible tamping method; and finally, putting the alloy material into the lining barrel, and integrally sintering the crucible by adopting a certain sintering process. The method for preparing the large-capacity calcareous crucible can tamp the calcareous crucible with long service life and large capacity, effectively improves the purity of vacuum induction smelting high-temperature alloy, prepares the alloy material with excellent performance, and enlarges the service range of calcium oxide in the aspect of vacuum metallurgical crucibles.