Embodiments of the present invention provide a decision feedback equalizer, which includes: a receive end, configured to receive a first differential signal, and input the first differential signal to the superimposer; a superimposer, configured to superimpose the first differential signal on a square-wave signal output by a adjusting unit to obtain a second differential signal; the adjusting unit, configured to perform phase and/or amplitude adjustment for a second square-wave signal; the first decision device is configured to compare a voltage amplitude of the second differential signal with a set value, and output a first square-wave signal; the second decision device is configured to compare the voltage amplitude of the second differential signal with a voltage amplitude of a signal adjusted by the adjusting unit, and input an obtained second square-wave signal to the adjusting unit. The embodiments of the present invention can reduce data edge jitter.