Nuclear spin generator (NSG) is a high-frequency oscillator which generates and controls the oscillations of the motion of a nuclear magnetization vector in a magnetic field. This system exhibits a large variety of chaotic behaviors and displays Much richer structures. So it is "a better archetypal system than the Lorenz system". Based on the property of passive system, the essential conditions were studied: by which nuclear spin generator system could be equivalent to passive system. Using Lyapunov stability theory, the convergence condition deciding the system's characters was discussed. In the convergence condition area, the equivalent passive system could be globally asymptotically stabilized by smooth state feedback. Simulation results are provided to show the effectiveness of the proposed control method. (C) 2008 Elsevier Ltd. All rights reserved.