A working Channel, CH, tuning method, comprising: providing, by an Optical Network Unit, ONU, for an Optical Line Terminal, OLT, at least one of the following information: a working CH corresponding to minimum power consumption or power consumption information corresponding to the ONU in different CHs (S302); receiving, by the ONU, a tuning message which indicates a first working CH and is provided by the OLT according to the provided information (S304); and tuning, by the ONU, a working CH to the first working CH indicated by the tuning message (S306); or, acquiring power consumption information corresponding to an Optical Network Unit, ONU, in different CHs (S402); and selecting a working CH corresponding to minimum power consumption for activation (S404); wherein in a process of providing the information for the OLT (S302), the information is provided for the OLT in a following manner: under a condition that the ONU is under a registration activation response process, the information is provided for the OLT through a Serial_Number_ONU response message responsive to registration activation; under a condition that the ONU is in a working state, the information is provided for the OLT through at least one of: a Serial_Number_ONU working message, a Physical Layer Operation Administration and Maintenance, PLOAM, message or an ONU Management Control Interface, OMCI, message. providing, by an Optical Network Unit, ONU, for an Optical Line Terminal, OLT, at least one of the following information: a working CH corresponding to minimum power consumption or power consumption information corresponding to the ONU in different CHs (S302); receiving, by the ONU, a tuning message which indicates a first working CH and is provided by the OLT according to the provided information (S304); and tuning, by the ONU, a working CH to the first working CH indicated by the tuning message (S306); or, acquiring power consumption information corresponding to an Optical Network Unit, ONU, in different CHs (S402); and selecting a working CH corresponding to minimum power consumption for activation (S404); wherein in a process of providing the information for the OLT (S302), the information is provided for the OLT in a following manner: under a condition that the ONU is under a registration activation response process, the information is provided for the OLT through a Serial_Number_ONU response message responsive to registration activation; under a condition that the ONU is in a working state, the information is provided for the OLT through at least one of: a Serial_Number_ONU working message, a Physical Layer Operation Administration and Maintenance, PLOAM, message or an ONU Management Control Interface, OMCI, message. under a condition that the ONU is under a registration activation response process, the information is provided for the OLT through a Serial_Number_ONU response message responsive to registration activation; under a condition that the ONU is in a working state, the information is provided for the OLT through at least one of: a Serial_Number_ONU working message, a Physical Layer Operation Administration and Maintenance, PLOAM, message or an ONU Management Control Interface, OMCI, message. <EOS>