Uniform alpha-MoO3 nanowires with the diameter of 60-100 nm and the length of 10-40 mu m were fabricated in high yield through a facile non-hydrothermal method. The fabrication process involved acidifying an ethylenediamine solution of molybdenum acid and subsequent calcinating treatment without any hydrothermal procedures. Ethylenediamine was found to play a crucial role for the formation of alpha-MoO3 nanowires under the present conditions. Thus-prepared alpha-MoO3 nanowires as supercapacitors exhibited much larger capacitance and better cyclicity than the conventional particulate counterpart.