The　cables　in　a　cable-stayed　bridge　usually　possess　low　inherent　damping　and　are　prone　to　wind-induced,　traffic-induced,　and　wind-rain-induced　vibrations.　This　paper　establishes　an　active　control　algorithm　using　the　stiffness　control　method　to　suppress　wind-rain-induced　vibration　of　prototype　stay　cables.　By　neglecting　the　axial　inertia　force　and　the　modal　coupling,　the　governing　equations　of　motion　of　wind-rain-induced　vibration　control　of　prototype　stay　cables　with　active　stiffness　control　algorithm　are　first　derived.　The　fourth-order　Runge-Kutta　method　is　then　introduced　to　find　the　numerical　solutions　to　the　problem.　Extensive　parameter　studies　have　been　carried　out　for　investigating　the　features　of　the　control　method　as　a　design　guideline.　Copyright　©　2007　John　Wiley　&　Sons,　Ltd.