In this study, a mixed numerical-analytical model is presented for investigating the transient response of a rectangular thin plate under low-velocity impact. Elastic-plastic behavior, rotational inertia and structural damping of the plate are considered in the governing differential equation. A modified contact model is used to determine the contact force between the plate and the impactor. The spatial domain of the plate is discretised by the finite difference method to capture the propagation of bending waves at the contact surface and the variation of stress along the thickness direction. Explicit integration algorithm is employed to solve the dynamic response of the plate with a time step satisfying the CFL condition. The theoretical results are validated by numerical experiments, and it can be seen that the mixed model is accurate and efficient. In addition, the eccentric impact behavior of the thin plate is investigated parametrically using the mixed model.