The periodic motion and Poincaré maps of a two-degree-of-freedom vibro-impact system are studied in this paper.The stability of the periodic motion is determined by the eigenvalues of the Jacobian matrix.It is shown that there exist Hopf bifurcations and period-doubling bifurcations in the vibro-impact system under suitable system parameters.The quasi-periodic responses of the system represented by invariant circles in the projected Poincaré section are obtained by numerical simulations, and routes to chaos are described briefly.