With the increasing needs of data transmission rate in wireless communication, it has become a job with more challenge to study how to optimize signal detection from noise in multipath channels and to construct the best receiver in keeping with the certain criteria. From the point of view of optimal receiver design, the function of matching filter is derived and analyzed deeply, and a method of solving the whitening filter by means of minimum phase channel is proposed. The effectiveness and robustness of the sequence detection receiver scheme for eliminating inter-code crosstalk are verified, providing a performance limit reference for receiver design in multi-path channels. The simulation results show that: the performance of sequence detection based on Viterbi algorithm is superior to that of MMSE equalizer, even more than 10 dB in the bad channel with spectrum zero. For the number of less than 5 paths, the sequence detection method based on Viterbi algorithm can not only be adoptable but its computational complexity can also be acceptable.