An equalizer includes a first sampler, a second sampler, and an equalization circuit. The first sampler is used for sampling an input data to generate an output data, and the second sampler is used for sampling the input data to generate an edge information. The equalization circuit is coupled to the first sampler and the second sampler, and includes an equalization unit and a control unit. The equalization unit performs an equalization operation on an original input data in order to generate the input data according to a plurality of tap coefficients. The control unit is coupled to the equalization unit, for adjusting the plurality of tap coefficients according to the output data and the edge information.