The utility model relates to a na ni district cofferdam structure, distinguish soil layer, support, geotechnological cloth layer and sand hill including na ni, the support includes staking out pole, horizontal connecting rod and oblique supporting rod, staking out pole and horizontal connecting rod constitute and have the vertical cofferdam frame that encloses the face, and the bottom entry of staking out pole is fixed in na ni district soil layer, and oblique supporting rod is fixed in one side of cofferdam frame, oblique supporting rod's upper end and cofferdam frame attach, and oblique supporting rod's lower extreme supports nani district soil layer, geotechnique's cloth layer is walked around the upper end of cofferdam frame and is covered the both sides of cofferdam frame, and it is fixed to pressing that the sand hill is passed through in the lower part of cofferdam frame both sides in geotechnological cloth level, geotechnique cloth layer includes inner cloth layer and outer cloth layer, and in inner cloth layer's the lower extreme embedding na ni district soil layer and by the sand hill compaction, outer cloth layer's lower extreme is laid on nani district soil layer and bythe sand hill compaction. The utility model discloses easy equipment, with low costs, and it is reliable.