Disclosed is a method for spreading data symbol frequency domain information in power line carrier communication, wherein when generating a data symbol in power line carrier communication, multiple times of frequency domain information diversity copy is used in place of the conventional ROBO copy, such that the diversity copy is independent of channel time-varying property, but only dependent on channel characteristics; as such, diversity copy is implemented within the same symbol, which facilitates simplifying the processing circuit of frequency domain and meanwhile enhances communication reliability.