An enhanced 8-VSB reception system and E8-VSB data demultiplexing method, by which an E8-VSB signal can be stably received as well as a previous ATSC 8VSB signal, is disclosed. Herein, the enhanced data are coded at 1/2 code rate and 1/4 code rate in the new E8-VSB transmission system compatible with the conventional ATSC 8VSB system, respectively. The 1/2 and 1/4 enhanced data are multiplexed by 164-byte packet unit according to the previously determined multiplexing format and further pre-processed to output as the format of the MPEG transport packet. And, the pre-processed enhanced data and the main data are multiplexed again by 188-byte packet unit according to the previously determined multiplexing format. The E8-VSB map information, which was inserted in the field sync section in the E8-VSB transmission system to be transmitted, is extracted to generate the information indicating the attributes of the respective E8-VSB data. The normal data, 1/2 enhanced data, and 1/2 enhanced data are separated from each other to be decoded in the channel decoder.