The invention discloses application of SFN (sulforaphane) to preparation of medicine for treating leukemia, and belongs to the technical field of novel purpose of the SFN. The application is characterized in that according to the application of the SFN to the preparation of the medicine for treating the leukemia, the SFN promotes the leukemia apoptosis through raising Bax genes and Caspase-3 genes and reducing Bcl-2 genes for further inhibiting the multiplication of leukemia cells. The influence of the SFN on the acute leukemia cell KG1a and K562 apoptosis is systematically discussed for the first time; a result proves that the SFN can promote the acute leukemia apoptosis through regulating and controlling the Bax genes, the Bcl-2 genes and the Caspase-3 genes; the result belongs to the theoretical breakthrough and has the potential clinic application significance; a fire-new thought and potential treatment path is provided for leukemia treatment.