The invention relates to a time-frequency domain combining method for OFDM multi-antenna signal transmission, belonging to technology field of digital information transmission. First, original information produced by transmitting terminal is sequentially subject to source coding, channel coding, digital modulation, space-time coding and TFU-OFDM modulation; the modulated signal is transmitted through multi-antenna; the received signal is sequentially subject to TFU-OFDM demodulation, space-time decoding, digital demodulation, channel decoding, source decoding to acquire original information. The invention has merits that TFU-OFDM solves frequency selective fading and time selective fading problem arising from multipath transmission and Doppler frequency offset in broad band wireless mobile communication system; the MIMO technology with space diversity multiplexing characteristic promotes data transmission rate of communication system and spectrum effectiveness, enhances system capacity of communication system, promotes communication reliability.