| According to the results of field geological survey and regional geological data, the geological background and Neotectonic characteristics in Changning earthquake area is analyzed, the seismogenic structure of this earthquake is discussed，and the seismogenic model of this area is finally given. The regional neotectonic movement has two main characteristics: the whole intermittent weak uplift, and no obvious activityin Late Quaternary along the faultsand weak seismic activity. The epicenter is located on the Shuanghe, Changning, great anticline, at which there are the old NE direction compressive stress field and clockwise rotation stress field. In the core and wing of the great anticline, two groups of NW and one group of NE joints are generally developed, which are characterized by regional distribution and form equidistant structural fracture zone (weak zone). The seismic sequence shows an obvious NW linear belt, and the fracture pattern is mainly thrust with strike slip component. The analysis shows that the Changning earthquake may be resulted from structural strengthening, transfixion and fracture of NW longitudinal joints along Shuanghe anticline under the action of ancient stress field.