A clock synchronization method includes receiving, by a receiving apparatus, a plurality of data blocks using a plurality of physical layer modules (PHYs), where the plurality of data blocks include a plurality of head data blocks, performing, by the receiving apparatus, timestamp sampling on the plurality of data blocks to generate a plurality of receipt timestamps, aligning, by the receiving apparatus, the plurality of receipt timestamps using a first receipt timestamp as a reference, generating, by the receiving apparatus, a clock synchronization packet based on the plurality of data blocks, and writing, by the receiving apparatus, a value of a second receipt timestamp into the clock synchronization packet, where the second receipt timestamp is a receipt timestamp that is of a second data block and that is determined based on the plurality of aligned receipt timestamps.