This application discloses a quick acknowledgement reply method and apparatus, where the method includes the following steps: receiving, by an acknowledgement sending apparatus, a data frame sent by an acknowledgement receiving apparatus; and after successfully decoding the data frame, generating and replying with, by the acknowledgement sending apparatus, an acknowledgement ACK frame, where the ACK frame includes a physical layer part; and the physical layer part includes: a legacy short training field L-STF, a legacy long training field L-LTF, and identification information of a station. This application is advantageous in low overheads.