The present invention relates to the field of communications technologies and discloses a method, an apparatus and a system for transmitting SDH/Sonet section overhead bytes, which reduce a burden of an intermediate node of a PTN network in a process of transmitting DCC bytes in the PTN network. In the present invention, a pseudo wire is established between a local end node and a peer end node. The local end node separates target overhead bytes from section overhead bytes of an SDH/Sonet frame, where the target overhead bytes include DCC bytes; packages the target overhead bytes to obtain a dedicated overhead packet; and sends the dedicated overhead packet to the peer end node, where the dedicated overhead packet is transmitted as a service packet of the pseudo wire. The embodiments of the present invention are mainly applied to a process of transmitting an SDH/Sonet service in the PTN network.