A method and an apparatus for sending an Ethernet physical-layer OAM overhead, and a method and an apparatus for receiving an Ethernet physical-layer OAM overhead are disclosed herein. A method for sending an Ethernet physical-layer OAM overhead includes: adjusting the order of sending a payload block and part of Inter-Packet Gaps (IPGs) in a data stream to be transmitted; and when receiving a request for sending an OAM overhead, substituting the OAM overhead for the part of IPGs, and sending the OAM overhead before sending the payload block. Through the present invention, the order of sending IPGs and payload blocks in an MAC data stream can be adjusted, and the OAM overhead can be sent in time.