Abstract: In order to depress or suppress sidelobe level of echo signal after channel equalization, the sidelobe level of suppression method is given, that is, increase mismatch filter after the equalizer. The simulation results show that, increasing the equalization filter length, although can lower sidelobe level to a certain extent, but it has a longer processing time. If increasing the mismatch filter after the equalization, not only can effectively suppress the sidelobe level, and the processing time is shorter. So in practical applications, it is best to choose the method of increasing the mismatch filter after equalization filter to suppress the sidelobe level, so that improve the signal-to-noise ratio of the output signal and increase the detection performance of receiver