Abstract: A calculation model for submerged floating tunnel (SFT) subjected to impact loading is developed. The distributed mass of the cylindrical shell is converted into concentrated mass at the impact position. Based on energy conservation during deformation process, momentum conservation during impact and the relationship between displacements and internal forces, the analytical solution is obtained, which considers the effects of added water mass and system damping. In order to verify the analytical result, a finite element model of impact is established using the ANSYS/LS-DYNA code. A simulation example is given to examine the effects of impact position and impact velocity on the maximum radial displacement at impact position. Both cases with and without added water mass are considered. The analytical solution and numerical simulation are compared, showing that they are in good agreement. The effects of system damping on the results are obtained by further numerical simulation. During the numerical simulation, the maximum von Mises stress at impact position can also be obtained.