There are provided a method for selecting an optimal beam to improve digital broadcasting receiving performance, and a digital broadcasting receiving apparatus using the same. The method includes the steps of: a) calculating a mainpath Signal to Multipath signal and Noise Ratio (SMNR) based on a channel impulse response for a plurality of beams which are formed according to steering directions from output signals of antennas, wherein the output signal of each antenna has different phase shift according to location of antenna element; b) selecting a predetermined number of beams having a high SMNR value by comparing the calculated SMNR value for respective beam; c) calculating a mainpath Signal to Dominant Multipath signal Ratio (SDMR) based on a channel impulse response corresponding to the selected beam; and d) selecting a beam output signal having the biggest SDMR value by comparing SDMR values calculated in selecting a predetermined number of beams.