The invention relates to a method for reusing the wavelength of an arrayed waveguide grating switching structure. The method comprises the step decomposing an arrayed waveguide grating switching structure constructed by a large-scale arrayed waveguide grating into an arrayed waveguide grating switching structure constructed by small-scale arrayed waveguide gratings. According to the wavelength reusing method provided by the invention for the arrayed waveguide grating switching structure, a large-scale AWG (Arrayed Waveguide Grating) is decomposed into a combination of a plurality of small-scale AWGs, and each input and output node can be equipped with multiple optical transceivers can be by using the decomposition method, thereby being capable of reducing the wavelength running range, and enabling the wavelength to be reused.