Disclosed are a load modulation-based beamspace MIMO transmission method and apparatus. The beamspace MIMO transmission apparatus may include a plurality of impedance loading circuits each including a plurality of imaginary impedance devices, a beamspace MIMO control unit calculating loading values of the plurality of imaginary impedance devices, corresponding to a spatial multiplexing orthogonal frequency division multiplexing (OFDM) sample, and an RF chain unit generating a first signal having a predetermined carrier frequency.