The super-long truss structure is the core component of the subsequent high spatiotemporal resolution spacebased remote sensing load, and the establishment of its efficient dynamic model is the key to achieve high-precision vibration control. In order to establish an efficient and accurate dynamic model, firstly, according to the periodic characteristics and vibration deformation characteristics of the super-long truss structure, the displacement at the center of the periodic element is used to characterize the spatial displacement of the whole truss structure.two kinds of strain energy expressions for considering the local deformation characteristics of the truss structure are derived respectively, and then, according to the Hamiltonian principle and boundary conditions, two different equivalent dynamic models are established. Finally, through the comparative analysis of the inherent characteristics of the two equivalent models and the superlong truss structure, the effectiveness of the equivalent modeling and the necessity of considering the local deformation characteristics to improve the accuracy of the model are verified.