An HE-LTF transmission method is provided, including: determining, based on a total number NSTS of space-time streams, a number NHELTF of OFDM symbols included in an HE-LTF field; determining a HE-LTF sequence in frequency domain according to a transmission bandwidth and a mode of the HE-LTF field, where the HE-LTF sequence in frequency domain includes but is not limited to a mode of the HE-LTF field sequence that is in a 1× mode and that is mentioned in implementations; and sending a time-domain signal according to the number NHELTF of OFDM symbols and the determined HE-LTF sequence in frequency domain. In the foregoing solution, a PAPR value is relatively low.