The present disclosure relates to communication technologies and discloses a method and apparatus for multi-antenna transmitting based on spatial-frequency encoding. The method includes: performing spatial-frequency encoding on input data and outputting encoded data; mapping the encoded data to the same sub-carrier of each antenna in an antenna group; adding a phase shift to the encoded data on different sub-carriers of each antenna; OFDM-modulating the phase-shifted encoded data on each antenna; and transmitting the OFDM-modulated data by transmit antennas.