Abstract: To reduce the computational complexity of the traditional partial transmit sequence (PTS) algorithm in the multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) system, a modified PTS algorithm combining time domain and space domain signal processing is proposed. In the time domain, subblocks are operated by cyclic shift to achieve more candidate sequences. In the space domain, subblocks are switched between the antennas to suppress the peak to average power ratio (PAPR). At the receiver part, the signals at each subblock multiply by different phase rotation factors and the sum of distances between the signal and its nearest constellation points is calculated to realize the blind detection of the signals. The simulation results show that the proposed metho can reduce the PAPR effectively. In addition, compared with the traditional PTS algorithm, the proposed method can reduce the complexity significantly and obtain similar bit error rate (BER) performance.