Provided is a data receiving device and method for shortening a channel switching time in a DMB system. The device includes a CDM channel for receiving a broadcasting signal from a DMB satellite, demodulating the broadcast signal, and generating a MPEG2-TS packet. a GOP buffer for receiving the MPEG2-TS packet, checking whether or not the received MPEG2-TS packet is a key frame, and, when it is determined that the received MPEG2-TS packet is the key frame, initializing the buffer and storing the received MPEG2-TS packet as a GOP unit, a channel switch for switching a channel of a DMB service to the GOP buffer, an A/V reproducing buffer for buffering a predetermined amount of A/V data to reproduce the A/V data of the GOP buffer; and an A/V decoder for receiving and decoding the A/V data.