The maximum excavation depth from the ground to the base of the working well of Zhanjiang Bay subsea tunnel shield is about 47m，and the excavation depth is relatively deep.The deep-dug shaft structure is deeply buried in the full-head sand layer.The enclosure structure mainly consists of continuous wall and variable cross-section lining.This paper mainly analyzes the structure and stress design of the shaft project.The stress on the continuous wall and the inner village is relatively complex.It is necessary to consider the influence of quicksand geology at the bottom of the pit and large head difference between the inner and outer sides of the working well on the stability of foundation pit support.It is safe and economical to install relief wells in the pit by adopting the scheme of back sealing-relief wells，and drain water out through a series of wellhead.The experience can provide a reference for the design of deep excavation shafts with high water head along the coast in the future.