A method and apparatus for sharing frequencies in an orthogonal frequency-division multiplexing OFDM-based wireless communication system, wherein the OFDM-based wireless communication system comprises a base station and a mobile device that work within a radio frequency band, the method comprising: detecting an interference signal in the radio frequency band; setting by the base station, based upon the interference signal, interference indication information in a control header of a downlink frame to be sent to the mobile device, the interference indication information indicating a frequency range that is occupied by the interference signal in the radio frequency band; and sending by the base station the downlink frame to the mobile device, such that the mobile device may, based upon the interference indication information, avoid the frequency range where the interference signal is located.