The present disclosure discloses a signal equalization apparatus. A channel length estimation circuit determines a transmission channel length of the input signal such that a processing circuit retrieves predetermined feed-forward equalizer coefficients. A feed-forward equalizer equalizes the input signal according to operation feed-forward equalizer coefficients. An auto gain circuit amplifies the input signal according to an offset signal. A signal adding circuit adds the amplified input signal and a feedback adjusting signal to generate an added input signal. A data slicer generates a data-slicing result and the offset signal according to reference thresholds based on the added input signal. A feedback equalizer equalizes the data-slicing result to generate the feedback adjusting signal according to operation feedback equalizer coefficients. The feed-forward equalizer and the feedback equalizer keeps updating the equalizer coefficients such that a signal interference noise is eliminated rapidly to increase a signal and noise ratio of the system.