This paper presents a study on the generation mechanism of wind-induced vibration of suspenders of suspension bridges in the wake of bridge towers. The computational fluid dynamics (CFD) simulation is carried out to characterize the wind flow in the wake of bridge towers at different wind directions. The time series of force coefficients of suspenders are determined which clearly show the dominant frequency component associated with the vortex-shedding from the towers. A wind tunnel test program is also implemented to measure wind-induced vibration of suspenders at different wind speeds and directions. Results show that vortex-shedding from bridge towers has a strong influence on the aerodynamic forces of suspenders at a wide range of wind directions. The suspenders vibrate in both longitudinal and transverse directions. The large amplitude vibration of suspenders is observed when the vortex-shedding frequency from the towers coincides with the frequency of the suspenders.