In this paper,a frequency domain decision feedback equalizer is proposed for single carrier transmission with time-reversal space-time block coding (TR-STBC).It is shown that the diagonal decision feedback equalizer matrix can be calculated from the frequency domain channel response.Under the perfect feedback assumption,the proposed equalizer can approach matched filter bound (MFB).Compared with the existing time domain decision feedback equalizer,the proposed equalizer exhibits better performance with the same equalization complexity.