Abstract: In order to reveal the dynamical characteristics of transient thermal rub impact in a hot bending rotor system, the transient transfer matrix method was used to develop the dynamical equations of unsteady thermal rub impact through combining Riccati transfer matrix method with Wilson-θ method. The unsteady thermal rub impact was numerically computed and analyzed in the warm starting process of a multi-disk rotor, and the point rub impact and one-side wear-out faults of the hot bending rotor were simulated in steady-state temperature field. Some dynamical characteristics of unsteady thermal rub impact owing to the imbalance force and hot bending were therefore found. As a result, a theoretic and computational foundation is laid down for improving the stability of the rotor system to avoid or overcome such dangerous condition.