A data transmission method, a communications system and related apparatuses are disclosed. The data transmission method includes the following steps: a transmitter obtains channel information corresponding to channels between the transmitter and several receivers; the transmitter obtains a control vector corresponding to a receiver according to the channel information; the transmitter modulates data to be transmitted by means of one-dimensional modulation to obtain modulated symbols; the transmitter processes the modulated symbols and the control vector to obtain transmitted data of each antenna; the transmitter transmits the transmitted data to the receiver; the receiver receives the transmitted data in a predetermined spatial direction of received symbol. The present invention also discloses a communications system and related apparatuses.