Abstract: The span of a cable-stayed bridge is big, the structure is complex, and all members of the structure affect each other.The differential equation of vibration on pre-stressed suspended structures is derived through the theory of D'Alember and factors to affecting the frequency of pre-stressed structure are analyzed.These factors include the section area, elastic modular, length of cable, and mass of whole structure, whereas pre-stress is not inclucled.A way to adjusting the frequency of the cable-stayed flyover is developed through modification on section area of the cable on the basis of the concept of spring in series or in parallel by analyzing members of the cable-stayed flyover.The method using the design of one cable-stayed flyover is used in one community.