Embodiments of the present disclosure provide methods and devices for inserting and extracting a pilot sequence according to a pilot mapping indicating a location for inserting the pilot sequence in a plurality of time-frequency resources. One example method includes inserting, by a transmitter according to pilot mappings corresponding to Nt transmit antenna ports by using Nt orthogonal pilot sequences that are different from each other, a pilot sequence corresponding to each of the transmit antenna ports into OFDM symbols that are included in the pilot mapping corresponding to the transmit antenna port. There is a one-to-one correspondence between the Nt pilot sequences and the Nt transmit antenna ports of the transmitter, where Nt is a positive integer greater than or equal to 2. The pilot mappings corresponding to the transmit antenna ports are the same among the Nt transmit antenna ports.