The multi-walled carbon nanotubes-nafion film coated platinum electrode was prepared with multi-walled carbon nanotubes and nafion solution in the article.The structures of the multi-walled carbon nanotubes,nafion film,multi-walled carbon nanotubes-DMF film and multi-walled carbon nanotubes-nafion film were characterized by scanning electron microscopy（SEM）.The electrochemical behaviors of potassium ferricyanide at multi-walled carbon nanotubes-nafion flim modified electrodes were studied and compared with those at multi-walled carbon nanotubes-DMF modified electrodes and unmodified platinum electrode by cyclic voltammetry（CV）.The multi-walled carbon nanotubes-nafion film modified electrode exhibited a remarkable enhanced effect on the current response of potassium ferricyanide.A sharp reduction characteristic peak at 0.185 V was observed,and the intensity of peak increased 8.7 times as compared with that of unmodified platinum electrode.And the intensity of oxidizing characteristic peak at 0.231 V increased 2.7 times as compared with that of unmodified platinum electrode.The MWNTs surface has a big area,therefore,it could be used to enhance electronic transmission efficiency and improve the sensitivity.The studies also showed that the surface reaction of potassium ferricyanide at unmodified electrode is reversible reaction,but not at multi-walled carbon nanotubes-nafion film modified electrode.