Disclosed are an adaptive frequency domain resource configuration method, an apparatus, and a communications system. The method includes receiving, by a receiving apparatus, a pilot signal transmitted by a transmitting apparatus and feeding back channel information of a channel for transmitting the pilot signal to the transmitting apparatus by measuring the pilot signal, so that the transmitting apparatus divides a bandwidth frequency of the transmitting apparatus according to the channel information. The receiving apparatus can feed back the channel information to the transmitting apparatus according to the received pilot signal, so that the transmitting apparatus can divide the bandwidth frequency according to channel quality, and adaptive adjustment can be performed on a frequency domain resource of each subcarrier according to the channel information fed back by the receiving apparatus.