Abstract. The identification of deep-seated landslides is a difficult problem and its failure mechanism is a research hotspot. This paper mainly discusses a very attractive huge deep-seated ancient landslide, it is a very good case to go further research. About 15 years ago a large-scale abnormal geomorphy and geological phenomenon, containing a discontinuous stratum in output and color, was found in the new city of Fengjie, Three Gorges Project Reservoir, China. Two hypotheses for the interpretation of the abnormal phenomenon are a fault graben or a large-scale landslide. From then on continue collecting and analyzing relevant information, field investigation and test, now the results show that the fault graben, consisting of normal faults, could not have been formed under the north-south compressive structure stress of the local region. Meanwhile, a lot of unique geological features, interesting sliding trails and marks of the ancient landslide are discovered and identified in field and experiments. The deformation process and failure mechanism of the ancient landslide are clearly reappeared by a large centrifuge model experiment. Its failure mechanism can be analyzed as "creep-crack-cut". The experiment strongly confirms that it is a huge deep-seated ancient rock landslide. And the failure precursor and key factors of rock slope are discussed. At last, the stability analysis shows that the landslide as a whole is stable and the secondary landslides at the front are basically stable. The results provide a technical support for decision making of the land use planning and construction of the new city, Fengjie.