Abstract: To study the vibration response of a submerged floating tunnel tether subjected to a random excitation, a non-linear random vibration equation of the tether is set up by taking the sag of the tether into account, which is analyzed by the Monte Carlo method. It may be concluded that, the displacement and velocity root mean square response of the tether subjected to a zero-mean Gaussian white noise excitation tends to be a fixed value after a certain period of time; the displacement and velocity root mean square response of the tether increases with the root mean square of excitation; due to the damping force of water, the displacement and velocity root mean square response of the tether decreases rapidly compared with that of a tether in air.