Space debris detumbling technology can be an effective supplement to the direct capture capability of space robot for simplifying and completing the active debris removal mission. This paper focuses on the optimal contact control for space debris rotation eliminating and nutation damping. Firstly, the space debris attitude motion is analyzed. The space debris detumbling strategy is presented with a designed spring contactor as the detumbling tool. Then, the contact detumbling dynamic models are established, including the spacecraft dynamic models, the contact detection method and the contact force model. Furthermore, an optimal contact control method is developed in order to reduce the three-axis angular velocities of space debris and suppress the nutation at the same time. The stability of the control method is proved by using the Lyapunov argument and the condition for nutation convergence is analyzed. Finally, numerical simulations are carried out to verify the optimal contact control method proposed in this paper. The results illustrate that the control method is effective for space debris detumbling and has certain robustness to the measurement and identification errors.