To adapt to the development of marine engineering to deep water,a combination of tension mooring and combined stiffness mooring system is proposed and applied to floating breakwater.A numerical model of the floating breakwater with tensioned combined stiffness mooring is established based on the high-order boundary element method under the potential flow theory,and the accuracy of the numerical model is proved by comparing the bypassing wave force with the classical literature.Setting the incident wave as a second-order Stokes wave,the hydrodynamic characteristics of the floating breakwater under the influence of combined mooring stiffness and cable length factors are analyzed and the mooring tension safety factor is calculated.The results showed that the heave motion curves of the floating breakwater under each wave period exhibit obvious irregular phenomena,and the nonlinear influence of mooring geometry is significant.Different mooring stiffness schemes have different degrees of geometric nonlinearity and large differences in breakwater motion amplitude,and the statistics of breakwater motion displacements for different cable lengths are close to each other with similar motion characteristics.Finally,by comparing the safety factors of mooring tension,the parameters of the tensioned combined stiffness mooring system suitable for the designed wave conditions are derived.