Abstract: A model of self-excited aerodynamic forces acting on a section of bridge deck with additional surface attached belowthe trailing edge is established. In the engineering background of a suspension bridge tender project, taking the bridge and the airflow as a whole system, the effectiveness of the surface in the flutter stability of the system is studied by a multi-mode flutter analysis approach. The analysis shows that the additional surface attached belowthe trailing edge is an effective aerodynamic means for suppressing the flutter of suspension bridges.