A method for manufacturing a cathode tip of electric field emission device includes depositing conductive layer and undoped silicon layer on the insulator substrate sequentially; forming a tip-mask pattern on the selected area of top of said undoped silicon film and etching said undoped silicon film isotropically and then anisotropically in turn, so that the silicon film is formed as cone-like having cylinder; and removing the tip-mask pattern, implanting ion into the etched silicon layer and removing the ion implanted silicon layer using the wet etch process.