An equalizer is disclosed. The equalizer includes a filter, configured to receive the first transmission signal, to perform a filtering operation on the first transmission signal according to a feedback signal to generate an output signal; a first slicer, configured to generate a first sliced signal according to a signal level of the output signal and to adjust an amplitude of the first sliced signal according to an amplitude control signal; a boost control module, configured to generate the feedback signal according to the output signal and the first sliced signal; and a control circuit, configured to receive a second transmission signal on the transmission line and to output the amplitude control signal according to an amplitude of the second transmission signal.