At present, the design of engineering structures is generally based on the mature linear vibration theory, without considering the influence of nonlinear and multiscale characteristics, which leads to the frequent occurrence of various vibration problems and the failure of vibration reduction measures. Firstly, this paper takes the mass-spring system as an example, and carries out the parametric influence of the stiffness ratio and mass ratio on the system vibration, of which the result points out that the stiffness ratio has a significant influence on the system modal property. In addition, the research overview on the long-span bridge dynamics is briefly discussed. From the perspective of system global dynamics, the concept of a multistiffness scale of engineering structure is proposed based on nonlinear dynamics analysis and finite element analysis. The global modes, local modes and mixed modes of multi-stiffness scale coupling systems based on different stiffness scales are analyzed and pointed out. The research may lay the foundation for establishing the global dynamic model and theory of bridge and studying the nonlinear dynamics of the bridge.