During excavation in permeable soil with high water table,easy to occur flow of sand,piping and other damage phenomena.Groundwater control is the key to ensuring safe of a pit construction.Based on an engineering project,the dewatering program of a deep excavation in the thick sandy aquifer close sea is introduced.The dewatering test results show that the program fulfil the dewatering requirements,and the deep well is suitable for this kind of deep excavation.