Wavelength allocation method and device

The present invention relates to a wavelength allocation method and a device. The wavelength allocation method comprises that an optical line terminal receives the operating parameter values transmitted by a current on-line optical network unit, the operational parameter values are N operating parameter values of a wavelength tuning area when the current on-line optical network unit utilizes N available wavelengths, the N operating parameter values correspond to N available wavelengths (N > 0); a wavelength is allocated to the current on-line optical network unit according to the operating parameter value; and instruction information is transmitted to the current on-line optical network unit, and the instruction information comprises the wavelength allocated to the current on-line optical network unit.