In this paper, the research object is the taizhou Yangtze River Highway Bridge, a triple-tower suspension bridge with the largest main span in this type. Firstly, a 3D finite element model for this bridge is established based on ANSYS software and its modal analysis is carried out through the subspace interaction method. The dynamic characteristics of this bridge are obtained and analyzed. Finally, the effects of the rise-span ratios, stiffness and configuration of middle tower, and the soil-pile-structure interaction on the dynamic characteristics of the triple-tower suspension bridge are investigated. The trend of the changes in dynamic characteristics with the above key parameters is analyzed. Results show that increasing the rise-span ratios or the along-bridge stiffness of the middle tower can improve the bridge′s flutter performance. These results can provide references for the dynamic design and study of the triple-tower suspension bridge.