Abstract: Unitary space-time codes were introduced to the digital audio broadcasting(DAB) system,and a multiple-antenna DAB system based on differential unitary space-frequency modulation(DUSFM) was proposed,which adopts a concatenation of convolutional encoder,time interleaver,frequency interleaver and DUSFM.In DUSFM-DAB,the receiver can perform demodulation without channel status information.Theoretical deduction proved that the DUSFM-DAB can obtain full spatial,temporal,and frequency diversities.By Monte Carlo simulation,with time-frequency selective fading 4×1 MIMO channel,to achieve a 0.001 bit-error-rate,the performance of the proposal scheme has a 6.5 dB SNR benefit compared with that of the original DAB,while the SNR benefit of CDD-DAB is 1.0 dB in the same condition,which verifies that the DUSFM-DAB has a higher diversity gain.