A method of producing perovskite nanocrystalline particles using a fluid mold includes a first operation for preparing a mixed solution including a first precursor compound, a second precursor compound, and a first solvent. A second operation for preparing a precursor solution by adding an organic ligand to the prepared mixed solution, a third operation for performing crystallization treatment after adding the prepared precursor solution to a reactor containing a fluid mold, and a fourth operation for separating the perovskite nanocrystalline particles from the crystallized solution through a centrifugal separator.