Abstract: Based on the STBC scheme, the combined effect of the transmitter and receiver I/Q imbalance, the front-end filter unmatch, CFO and frequency selective channel distortion for the presence at the same time in MIMO OFDM communication system was intensively studied , and an applicable joint equilibrium strategy was also proposed. The concrete implementation is that a frequency domain equalizer was firstly obtained through the analysis of the only presence of the transmitter I/Q imbalance and multipath channel interference in MIMO OFDM system. And then considering on the simultaneous presence of receiver I/Q imbalance and CFO, two time domain equalizers were also obtained. Finally, these time domain equalizers were transformed into the frequency domain, combined with frequency domain equilibrium technology to eliminate the transmitter I/Q imbalance and multipath channel interference. A comprehensively joint equilibrium technology, namely frequency domain per-tone equalizer, was proposed. The simulation results show that the frequency domain per-tone equilibrium technique for the proposed MIMO OFDM system can be extended to other higher order STBC system, and the BER performance of the system after equilibrium using the proposed equilibrium technique is improved obviously.