The present patent application provides a method, an apparatus, and a system for generating a timestamp. The method includes: receiving, by a data packet processing unit, a data packet sent by a physical layer transceiver unit or an upper layer, and identifying whether the data packet is a precise time synchronization protocol PTP data packet, and if the data packet is a PTP data packet, generating, according to a physical layer delay provided by a physical layer delay acquiring unit and a non-physical layer delay provided by a non-physical layer delay acquiring unit, a precise timestamp and rewriting a timestamp field in the data packet.