This application provides a wavelength negotiation method of a multi-wavelength passive optical network, including: receiving a wavelength status table that is broadcast by an OLT over each downstream wavelength channel of a multi-wavelength PON system, where the wavelength status table is used to indicate information about available wavelengths of the multi-wavelength PON system and statistic information of registered ONUs of a corresponding wavelength channel; selecting an upstream transmit wavelength and a downstream receive wavelength according to the wavelength status table; and reporting information about the upstream transmit wavelength and information about the downstream receive wavelength to the OLT so that the OLT refreshes the wavelength status table. This application also provides a wavelength negotiation apparatus of the multi-wavelength passive optical network and a multi-wavelength passive optical network system.