A method of upgrading software through a software download in a Terrestrial Digital Multimedia Broadcasting (T-DMB) terminal includes the steps of announcing when the software is downloaded by receiving a T-DMB signal and analyzing a plurality of fast information groups (FIGs), determining whether the software is downloaded, storing ensemble information and download start time information; matching a current ensemble with the stored ensemble when time according to the download start time information elapses, and confirming a signaling message for informing that the software is downloaded and downloading the software.