Provided is a method for setting a digital broadcasting channel in a digital broadcasting receiver having a tuner and a demodulator. According to the method, when an automatic channel setting command is input by a user, a channel is selected using a tuner, and whether an NS flag is detected in each channel is judged. When the NS flag is not detected as a result of the judgment, a mode of each selected channel of the digital broadcasting receiver where signals are detected is judged from a VSB mode and a QAM mode. A channel map is constructed according to the judgment result. Accordingly, the method allows a subscriber or a manufacturer to automatically detect signals and store a corresponding channel in a channel map without separately setting cable broadcasting in cable digital TV broadcasting environment where VSB and QAM modes are provided.