Abstract: A numerical model for floating collar exposed to waves was set up by using the linear wave theory and the rigid body kinematics principle. In this paper, under the conditions of different wave heights（H=4.2~7.0 m）and wave periods（T=7.2, 8.6 s）, employing computer numerical simulation method, the forces on the mooring lines of the floating collar, the wave forces and the driving moments for the collar were calculated respectively. By comparing and analyzing, the calculated results showed that with wave height increasing, the forces on the mooring lines of the collar, the wave forces and the resultant moments for the collar all increased to some extent, and the force on the mooring line on wave-side and the horizontal wave force for the floating collar all had direct proportional relation with wave height. Under the conditions of different waves, the force on the mooring line on wave-side was far lager than that on lee-side, and the horizontal wave force was far lager than the vertical one.