Abstract: A method for fabricating semiconductor nanowire includes the following steps: providing a metal substrate in a reactor; filling the reactor with an inert gas; heating and maintaining the reactor in a reaction temperature, raising the pressure in the reactor to a first predetermined pressure, and then passing a reacting precursor into the reactor; keeping passing the reacting precursor to raising the pressure of the reactor to a second predetermined pressure; and, maintaining the second predetermined pressure for a predetermined duration, so as to form semiconductor nanowires on the metal bulk. Accordingly, the method of the invention is capable of forming semiconductor nanowires on metal substrate, so that the processes for fabricating semiconductor nanowires can be simplified.