Multibody formation constitutes a new architecture wherein the functional capabilities of a monolithic satellite are distributed, and some planned missions have begun to take advantage of the benefits offered by the use of satellite formations. The nonlinear dynamics of a two-chain, three-body formation system located on a circular orbit on the Earth is presented in this paper with the assist of nonlinear theory in astrodynamics. Different from only five libration points solved from the circular restricted three-body system, there exist sixteen equilibria for the chain system yielded by its geometry of the pseudo-potential function. For some hyperbolic equilibria, an iterative procedure is developed to correct numerically periodic orbits near them, which are referred as Lyapunov orbits in this paper. The invariant manifolds originating from those orbits are employed by Poincar茅 mapping to create the heteroclinic or homoclinic trajectories, and some non-transversal intersections between them are addressed in this paper.