Abstract: Based on the explanation and structural inversion on the 3D seismic profiles which crossing Chegu201 buried hill, a series of sandbox experiments had been finished. The results of experiment show: a. The spade faults and the deep ramp-flat faults in the structure are the specific characters of the main fault of Chegu201, and these specific characters formed the burial hill structure of this area; b. The reverse fault occurring the slope break area of primary fault was formed as a result of inversion of normal fault in extension; c. The complex structure distortion of this area is caused by compound function of hanging wall distortion of normal fault and non-homogeneous extension of flexible basement rock.