In the satellite-to-ground high-speed data transmission link, there are signal self-interference problems of symbols in the co-channel, as well as be-tween orthogonal and polarized channels. A multi-channel adaptive filter is designed by constructing a multichannel Wiener-Hopf equation, and the influence of five channel nonideal factors is suppressed to im-prove the BER performance. Experiments show that this method is effective to suppress the signal self-interference, and the BER floor is optimized from 1E-3 to 1E-7.