A method and an apparatus for sending signals to suppress outband interference effectively in a simple way includes: grouping subcarriers in a spectrum into edge subcarriers of the spectrum and non-edge subcarriers of the spectrum; precoding data to be sent to obtain modulated symbols of the data on the subcarriers, where the precoding makes every two adjacent edge subcarriers of the spectrum in the edge subcarriers of the spectrum carry a pair of modulated symbols with opposite polarities, and makes each of the non-edge subcarriers of the spectrum carry a modulated symbol with no polarity; and sending the modulated symbols of the data on the subcarriers. The embodiments of the present invention are applicable to a signal sending process.