Abstract: The vertical modes of long-span suspension bridges are always closely-spaced such that vortex-induced vibration may occur in more than one mode. To suppress higher-order vortex-induced vibration of suspension bridges, the application of MTMD which is demonstrated to be more effective and robust than TMDs was investigated. Firstly, the displacement response function of the girder installed with MTMD was deduced, using the empirical linear model developed by Scanlan. However, the aerodynamic damping and aerodynamic stiffness were not considered. Then, the minimal peak value of the displacement response function of the girder was defined as the optimization objective function and preliminary parameters optimization was accomplished by Matlab-based Genetic Algorithm. Lastly, the effectiveness and robustness of MTMD was discussed from the aspects of possible error in structural natural frequency and possible variation in structural mechanical damping ratio. The results indicated that it is feasible to ignore the aerodynamic stiffness parameter and the aerodynamic damping parameter in the initial procedure of parameters optimization and MTMD with proper frequency range and damping ratio can reach good balance between effectiveness and robustness, which is more suitable for the vortex-induced vibration control of suspension bridge than the traditional tuned mass dampers scheme (STMD).