Abstract: The water pressure load outside of a deep-water shield tunnel plays an important role in the security of the segment structure. Problems exist as a result of a large overburden and high water pressure outside of the tunnel:high installation risk for and a low survival rate of the osmometer, as well as less reliability regarding the data obtained. In this paper, a device and installation method are designed for the osmometer used outside the segment structure of the deep-water shield tunnel, and they are applied to monitor the water pressure outside a submarine shield tunnel in Zhanjiang, with satisfactory results obtained