Method for preparing quantum dot

This invention provides a method for preparing a quantum dot, including: dissolving a VIA group material in a first solvent to form a first precursor solution; dissolving a metal cation material in a second solvent to form a second precursor solution; after heating the first precursor solution and the second precursor solution separately, mixing them under specific conditions and continuously stirring to form a single-phase homogeneous liquid solution with a plurality of quantum dots; after cooling and centrifugally purifying the single-phase homogeneous liquid solution, dispersing the obtained plurality of quantum dots in a hexane solution; adding the hexane solution to an aqueous phase modified extraction solution and performing a reaction at a room temperature; and removing the hexane solution.