Abstract: Cables on cable-stayed bridges are susceptible to vibration by natural wind because of their low structural damping, especially in rainy and windy days. The vibration of cables can cause a series of problem such as the fatigue damage of anchorage structures. It is important to clarify the vibration mechanism in order to suppress the vibration. In this paper, by using Large-Eddy Simulation method, the flow fields and the Karman vortex intensities of cable with water rivulet at different positions are analyzed. The reasons why Karman vortex intensity is changed by water rivulet are discussed. It is indicated that small vortex shedding behind rivulet can weaken Karman vortex shedding. When wind velocity is higher than the Karman vortex induced vibration velocity and Karman vortex is weakened enough by small vortex shedding, the cables would vibrate.