In order to study the dynamic characteristics of the marine rotor-floating raft airbag system under the sway motion,the mathematical model of the system was established based on the short-bearing theory,and the dynamic behaviors were analyzed on numerical method.The effects of rotor speed,sway amplitude and frequency changes on the nonlinear dynamic characteristics of the system were investigated.The results show that comparing with the system without sway motion,the characteristic of system with is sway motion more complicated.The system is in quasi-periodic motion at the low speed of rotor under sway motion,and as the rotor speed increases,the system bifurcates then merges into a branch until chaos.With the increase of the amplitude of swaying,the vibration amplitude of the rotor increases.However,the increase of the frequency ratio will make the amplitude of the rotor smaller.