By the com prehensive study of geology,geomorphology,physical probing,trenching and boring,a subsurface fault is found along the west edge of Qinwang chuan basin,which stretches to the NNW and crosses the site of Zhongchuan airport extension.Some related issues of the fault,such as the dimension,segmentation and active time are investigated in detail and the effects of the fault to the site are scientifically evaluated.