Abstract: A terminal signal to interference plus noise ratio (SINR) information is one of the important bases for coding and modulation mode selection and resource allocation in multiple input multiple output orthogonal frequency division multiplexing (MIMO OFDM) systems.In this paper,a lower complexity method of SINR estimation is proposed for MIMO OFDM systems over frequency-selective multipath Rayleigh fading channels.In the scheme,a reduced-rank matrix is constructed utilizing the correlation between subcarriers,the smallest eigenvalue of covariance of this matrix is extracted to estimate SINR, and the error of SINR estimation is analyzed.According to the long term evolution(LTE) standards, the computer simulation is carried out.The results show that, when SINR is less than 30 dB, the proposed method requires only four continuous subcarriers as reference signals to reach an estimation error less than 0.2 dB, and it is insensitive to the Doppler shift.