A video decoding system is provided. When a DDR SDRAM is used as an external memory, MBs are rearranged and then stored to minimize memory access operations for the MBs at the DDR SDRAM and unnecessary additional word read operations caused by a DDR characteristic. Accordingly, the video decoding system can efficiently perform a memory access operation on MBs for video display and frame decoding by the video decoder. Specifically, the decoding system can reduce the total video decoding time, thereby allowing a surplus memory use time for additional functions of a digital broadcasting receiver.