Abstract: This paper is concerned with the characteristics of the parameter vibrations of the cable in cable-stayed-bridge, especially the vibration amplitude and the tension fluctuation. Using the method for geometric non-linear response analysis of structures under asynchronous excitation developed by the authors, the behavior of the parameter vibration of one cable-stay is studied using FEM. It is observed that the in-plane vibration of the deck can induce the out-of-plane symmetric vibration modes of the cable easily, leading to coupling vibration. However, the out-of-plane vibration of the deck can only induce the out-of-plane symmetric modes, and cannot induce the in-plane vibration of the cable easily. It is also found that the increase of damping of the cable dwindles the frequency bandwidth of large-amplitude vibrations and reduces the amplitude of vibrations, but enlarges the tension fluctuation. The results are in agreement with available analytical results and experimental phenomena.