The invention belongs to the field of preparation of nano materials and electromagnetic wave absorption, and relates to a method for simultaneously preparing a tungsten oxide quantum dot and a tungsten oxide nanowire. The method comprises the steps of firstly preparing a mixed solution comprising the tungsten oxide quantum dot, the tungsten oxide nanowire, an ethanol reactant and water from raw materials, namely ethanol and tungsten hexachlorideb by using a hydrothermal method, centrifuging the mixed solution at a rotating speed greater than 10,000r/min for over 10min and then preparing a supernate and a lower sediment of the tungsten oxide nanowire; and dialyzing the supernate in a liquid dialysis bag to remove impurities such as diethyl ether, ethanol and hydrogen chloride, wherein the remaining part is a pure tungsten oxide quantum dot solution. The length-diameter ratio of the prepared tungsten oxide nanowire can reach 64, the optimal electromagnetic wave absorption performance is obtained at 16.7GHz, the maximum reflection loss reaches -40.5dB, the method is simple in process, available in raw materials, low in preparation cost and high in preparation efficiency, the prepared product is good in quality, high in stability, good in application eminent and wide in market prospect, and large-scale production and manufacturing can be achieved.