A digital broadcasting receiving system and an equalizing method thereof are provided. The digital broadcasting receiving system includes: a demodulator for receiving and demodulating a RF (Radio Frequency) signal into a digital base band signal through A/D (Analog-to-Digital) conversion and carrier/timing restoration; an equalizer for compensating for a channel distortion included in the digital base band signal, through a coefficient updating depending on a fed-back error value; a MLSE unit for estimating a transmission signal by using a MLSE (Maximum Likelihood Sequence Estimation) way using a correlation of past symbols for an output of the equalizer, and outputting an estimated MLSE decision signal; and an error generating unit for generating an error value from a difference between an equalized signal of the equalizer and the estimated MLSE decision signal of the MLSE unit, to feedback the error value to the equalizer.