Abstract: Provided is a method of preparing nucleic acid molecules comprising: (a) a step of providing nucleic acid fragments constituting at least a portion of the complete sequence of a target nucleic acid; (b) tagging the nucleic acid fragments with barcode sequences; (c) identifying the sequence of the nucleic acid fragments tagged by the barcode sequences; and (d) recovering desired nucleic acid fragments among the sequence-identified nucleic acid fragments using the barcode sequences.