Abstract: The method of displacement back-analysis bridges between theory and practice, and provides a feasible and effective method for design and construction of rock engineering works. For resolving the problems about geological exploration, design and construction and reducing risk, the dynamic displacement back-analysis mode is established for advancing service tunnel. Based on the information feedbacks and forecasting the geology of main tunnel and judging the stability of surrounding rocks, the detailed measures and schemes for design and construction is proposed for the main tunnel. As necessary, adjustments and variations on the preliminary design parameters and schemes of the tunnel lining during construction are carried out. The timely feedbacking between design and construction contributes an effective method for successful tunneling below the sea water.