The hydroelastic theory is applied to analyze the elastic deformation of the floating collar under wave action. The effects of the floating collar's dimension, draught, elastic modulus, and wave conditions on the vertical displacement of the structure are investigated. The Discrete-Module-Beam (DMB) method is used to perform the hydroelastic analysis on the floating collar. The floating collar is discretized into a number of rigid sub-modules, the hydrodynamic loads acting on the floating collar are determined using the multi-rigid body hydrodynamic theory and the overall deformation of the structure is obtained using the curved beam element. The results show that: the vertical deformations of the floating collar at different positions are significantly different, the displacement amplitudes at the front and after points are larger than that in the middle, and this feature is more obvious with the increase of the wave frequency; the overall deformation of the floating collar decreases with the increase of diameter ratio and elastic modulus in the high-frequency range; the influence of draft on the vertical deformation amplitude of the floating collar is relatively small, and its main function is to intensify the oscillation phenomenon of the vertical deformation amplitude curve at the wave facing point in the high-frequency range; the influence of water depth on the vertical deformation of the floating collar varies at different positions and frequencies.