Abstract: Space joint-dominated structrues are widely used in many core components of modern spacecraft, such as solar arrays, antennas, etc. The dynamic behavior of space joint-dominated structure has a great impact on the stabilities and dynamic behaviors of spacecraft system. In order to indicate the dynamic behavior of the joint-dominated structure and then model the spacecraft system perfectly, it is importance to model the nonlinear subsystem and investigate its nonlinear dyamic behavior. This paper presents an approach to model the nonlinear subsystem and analyze it based on nonlinear normal modes. The advantages of this approach are to consider the joint- dominated structure as a multi-degrees system with local nonlinear constrains and then define the nonlingar normal modes as a movement on the invariant manifolds.