New use of icariin and Epimedium flavaoids containing icariin is provided by the present invention. Specifically, uses of compounds of Formula I or Epimedium containing compounds of formula I, Epimedium flavanoids, or extracts of Epimedium in manufacturing medicaments for treating, preventing, reducing and/or relieving diseases and/or conditoins related to neural myelin sheath impairments, or use of above materials in manufacturing medicaments for relieving demyelination and/or promoting repair of myelin sheath are provided by the present application, wherein, R1 is selected from H, halogen, —C1-6 alkyl, and —C(O)—C1-4 alkyl