Device and method for real time monitoring, and providing of useful program specific information (PSI) of a program received from a digital TV broadcasting system to a watcher, wherein, when broadcasting program PSI is changed, the change of the PSI is detected by monitoring a PMT in a PSIP, and facts of the change or addition of additional functions for a program following the change or addition of the PSI of the digital broadcasting program is reflected and informed to a watcher.