The sequence stratigraphy which originates from the shoreline siliciclastic sedimentary environment has been used in the fluvial strata which have a link with the sea level changes. It results in forming the conventional systems tracts models of fluvial sequence which include lowstand systems tract(LST) and transgressive systems tract(TST) and high stand systems tract(HST). With deep research in the inland sedimentary environments which have not correlated with the sea level changes, the early division of fluvial sequence that is used in the shoreline sedimentary systems tracts is inconsistent, so the concept of low- and high-accommodation systems tracts (LAST and HAST) (unconventional systems tracts) is raised, which represents the latest research progress in fluvial sequence stratigraphy. The concept convert from conventional systems tracts to unconventional systems tracts will provide important clues and ideas for studying complex fluvial deposition process and extracting stratigraphic record rules.