The cables in a cable-stayed bridge usually possess low inherent damping and are prone to vibrate by many factors. The wind-rain-induced vibration of the prototype stay cable is a special vibration problem associating with rain and wind. Many methods have been proposed to mitigate wind-rain-induced cable vibrations such as mechanical measures, aerodynamic modification, and control technology. Active control technique has significant control capability because of utilizing the external energy supply but it may not be realistic to large civil engineering structure due to enormous power demand. The two-stage control method has been proposed to control the wind-rain-induced cable vibrations of the prototype stay cable. The studies are carried out to investigate the energy cost features of the control forces as a design guideline.